Research on Collaborative Mechanisms of Railway EPC Project Design and Construction from the Perspective of Social Network Analysis

Abstract

With the promotion of Engineering Procurement Construction mode in railway construction projects, collaborative management between design and construction has faced increasing challenges due to complexities of the participants and the various professional fields involved in railway EPC projects. This paper aims to analyze the issues present in the collaborative management of railway EPC project design and construction. Utilizing the social network analysis methodology combined with the Wuli–Shili–Renli (WSR) system methodology, a network model was established to explore relationships between design and construction management. This study investigates network-influencing factors and proposes targeted measures to enhance project management efficiency. The findings indicate that coordination and communication mechanisms, organization building, interface management systems and design management systems represent core network elements that significantly impact railway EPC collaborative management. These elements are closely related to other network factors. The research not only advances design and construction coordination theory, but it also introduces new ideas for engineering practice.

1. Introduction

The EPC (Engineering Procurement Construction) general contracting model offers significant benefits in integrating the design, procurement, and construction phases, as well as facilitating efficient communication between the parties involved in the project [1]. This mode also proves effective in shortening the project timeline, controlling construction costs, and ensuring project quality. As a result, it has gained widespread attention and promotion throughout the construction industry. Railway EPC projects refer to railway construction projects using the EPC general contracting model. The general contractor assumes responsibility for the whole process, or part of the design, procurement, and construction phases, according to the contract entrusted by the owner. They are fully responsible for the cost, quality, and progress of the contracted project [2]. Many large- and medium-sized railway projects in China have adopted the EPC model, such as the Yantong Railway Project, Hangzhou–Quzhou Railway Project, Karamay–Tacheng Railway Project, Hangzhou–Shaoxin–Taizhou Railway Project, and Shanshan Railway Project. Railway engineering projects often have long construction periods and frequent overspending [3]. Due to the complexity of railway projects, the general contracting model is usually led by design institutes. The general contractor supervises the design, procurement, construction, and other work, according to the contract. However, railway design institutes lack experience in general contracting projects, resulting in an immature application of the general contracting management model and insufficient collaborative management capabilities in project design and construction. Therefore, it is essential to establish a collaborative management mechanism for design and construction.

Railway construction projects are characterized by lengthy construction times [4], significant investments [5], and high quality standards [6]. Railway lines typically span multiple locations and require extensive coordination, making railway projects inherently unpredictable. Unlike other projects, the construction management team plays a more active role and exercises greater control over the project [7]. Although most of the risks of the owner are transferred to the EPC general contractor through the EPC contract, the control rights entrusted to the contractor are often insufficient. Additionally, the involvement of the operating unit in the project construction increases risks for the EPC general contractor. Linear engineering projects have multiple lines and vast geographical details to consider [8]. Unfortunately, it is often difficult to obtain accurate survey results during the feasibility stage of the project. Furthermore, the geological prospecting data provided by units in the early stages of the project are insufficiently accurate or detailed. Railway engineering geological surveys are costly and time-consuming. As a result, bidders are often reluctant to conduct detailed geological surveys before bidding. This leads to bidders who cannot accurately assess the engineering geological risks along the railway line and increases risk during project implementation. Railway EPC projects are associated with both foreseeable and unforeseeable risks, requiring exceptional integrated management abilities from general contractors.

At present, the research on railway EPC projects mainly focuses on project key success factors, risk management [9], cost management [10], quality management, project stakeholders management, interface management, and knowledge management, as well as the combination of the EPC mode and other modes [11]. Nikjow et al. [12] adopted the method of a structured questionnaire survey, and explored the key influencing factors that caused the delay of the high-speed rail EPC project schedule according to the evaluation results of the relative importance index (RII). Wang et al. [13] took international EPC projects as the research object, combined the ISM method and the MICMAC method, established the relationship between 25 risk factors, and put forward risk management suggestions accordingly. Kim et al. [14] developed the DECRIS model to evaluate the schedule and cost management performance of key milestone nodes of large-scale EPC projects. This method can not only weigh the prevention and control of schedule risk and cost risk, but also predict cost overruns and optimize them. Shen et al. [15] considered that EPC projects increase the complexity of the working interface between stakeholders, and developed a trust-based model. The study found that trust, openness and communication between organizations can all have a positive impact on interface management. Sun et al. [16] established a tripartite evolutionary game model to test the strategic behavior changes of the government, owners and general contractors in applying Building Information Modeling (BIM) in EPC projects, which provides valuable management inspiration for the government to promote the development of BIM. However, most researchers have focused on analyzing the key success factors and risk management of EPC projects by studying the three stages of design [17,18], procurement [19], and construction [20] separately, while paying less attention to the coordination among these stages. However, to fully leverage the benefits of the EPC project management model, which allows the general contractor to take a holistic view of the project, improve efficiency, and increase project delivery rates, it is essential to ensure effective integration between the design and construction phases.

Collaborative construction project management encompasses the entire project life cycle [21], with the aim of mitigating participant obstacles and minimizing waste to ensure high-quality project completion. This approach involves coordinated management of resources and elements in terms of function, process, space, and time. Overall, it promotes interrelated and cooperative project management behavior. The research on the collaborative management of engineering projects includes the collaborative management of objectives, organizations, technologies, resources and other elements. The research content includes an evaluation model of the degree of collaboration and an information-management platform. [22]. Khouja et al. [23] considered that one of the reasons for the low productivity of the construction industry is the lack of synergy among the participating organizations. Through a systematic literature review, the collaborative relationships among 12 groups were sorted out. In order to solve the conflict of interests between different entities in construction waste treatment, Shen et al. [24] constructed a coupled model of system dynamics (SD) and multi-objective programming (MOP); the resource utilization rate of urban waste was finally improved. Elsayegh et al. [25] proposed the collaborative planning index, which is an objective scoring system that can help stakeholders to find factors that underperform, thereby improving project performance. In another study, Elsayegh et al. [26] used social network analysis to quantify the importance of collaborative factors, and suggested that future research should focus on the collaborative management of vision, goals, and the relationship between project participants. Dong et al. [27] combined a cloud service with GIS virtual reality to improve the algorithm of collaborative management of steel structure buildings and reduce the interference of personalized differences on the supply chain.

Internationally, an increasing number of academics are focusing on the collaborative management of large-scale infrastructure. Scholars from many nations and areas look at large-scale projects in their own countries to see how they may increase collaboration efficiency and delivery. Gondia et al. [28], for example, employed dynamic network modeling methodologies to increase project robustness and synergy. Sanchez-Silva [29] examined the advantages of introducing flexibility in design and construction using airport design and extension as an example. Walker et al. [30] developed a delivery strategy for a complicated project using an infrastructure project in Australia as an example to optimize cooperation. In a case study in Amsterdam, the Netherlands, Rosok et al. [31] found that collaborative decision making in XFN projects has additional complexity and requires the governance of uncertainty. Australian scholar Tokede [32] focused on how project coordinators affect trust-based partnerships in large infrastructure projects. Different countries have different national conditions, so the collaborative management methods of large engineering projects are also different.

Although collaborative management runs throughout the entire project cycle, in the FEED phase, it is especially important to pay attention to the coordination of design and construction, identify the key influencing factors, and then propose more direct response strategies. In previous studies, the stage division of the EPC management model is usually rough. If the management stages are divided more carefully, such as basic design, detailed design, FEED, construction map design, etc., it is beneficial to reduce subsequent collaborative management problems. Collaborative management of railway EPC project design and construction is a vital communication, coordination, and management process throughout the railway EPC project construction. It aims to ensure the integration and deployment of personnel and resources in the project, enabling the seamless integration of design and construction businesses. Through effective sharing and collaboration of technology, information, resources, materials, personnel, etc., the construction goals can be accomplished more efficiently, resulting in a win–win situation for all stakeholders involved. However, there is little research on the collaborative management of railway construction design and construction under the EPC general contracting mode. Typically, scholars study the design and construction phases separately, rather than integrating them, to maximize the EPC model’s management effectiveness. Thus, a comprehensive and clear system of influential factors for design and construction collaborative management has yet to be developed.

We aim to answer three questions through our research. What kind of mechanism that promotes cooperation is included in the design and construction of railway EPC projects, based on theoretical background and practical examples? Which elements are crucial nodes in the relationship network of the construction cooperation mechanism of railway EPC projects? Which elements have a more significant role? How can the coordination between the railway EPC project’s design and construction be improved by combining the core network elements?

The structure of the rest of this article is as follows: Section 2 introduces the methodology of the paper, including data collection, the steps for constructing a relational network, and the characteristic parameters of the network structure. Section 3 summarizes the results, then constructs a relational network of collaborative mechanisms for railway EPC project design and construction. Finally, Section 4 provides conclusions and recommendations.

2. Research Design

In the process of dealing with a system project/problem, the Wuli, Shili, and Renli theory of WSR methodology corresponds to the objective existence that people face, the mechanism of intervention when people face the objective existence and its laws, and the relationship between all people and its changing process. Based on the Wuli–Shili–Renli (WSR) methodology, this study constructs the logical structure of the coordination mechanism for the design and construction of railway EPC projects, as shown in Figure 1. In the complex network system of coordination mechanisms for the design and construction of railway EPC projects, three types of elements are coupled and interact with each other, which can maximize synergy and reflect the superiority of the EPC model.

2.1. Data Collection

At the beginning, we used expert interview methodology to analyze the challenges of collaborative management in the design and construction phases of railway EPC projects. We interviewed experts who have been involved in EPC projects of the Yangda Railway (a typical EPC pilot project led by the design unit as a general contractor of the project), the Yantong Railway (a pilot project of the China Railway Group to develop a general contracting model for railway construction projects, the first high-speed railway constructed by using the EPC general contracting model in China), and the Hangshaotai Railway (the first privately held high-speed rail project, creating a precedent for the “PPP + EPC construction” model in the railway construction industry) to identify key problem areas. The data collected were then refined to identify design and construction coordination challenges encountered during the actual work. Interviews were semi-structured, and several sessions were held with the supervisor to ensure accurate and comprehensive research. These interviews invited a total of 10 experts who have participated in railway EPC projects, from design units, to construction units and supervision units. The results reflect best practices in railway EPC project management based on case-specific empirical discussions. The interview content was organized by extracting irrelevant content and expounding sentences on collaborative design and construction management issues. Key words that appeared on three occasions were examined to identify recurring challenges in practice that require a focus on the project management process. The findings are presented in

Table 1. Statistics on the frequency of problems.

Problem Summary	Problem Keywords	Frequency
Design optimization problems	Design constructability	5
	Willingness to optimize design	7
	Adoption of optimization suggestions	6
Process coordination problems	Design and construction progress coordination	9
Resource coordination problems	Design–construction relevance	7
	Design and construction fit	8
	Knowledge sharing	4
Organizational coordination problems	Organizational interface	8
	Staffing	5
	Personnel capacity	8

, which shows the frequency of challenges encountered.

Next, a list of influencing factors was drawn up, in line with the design–construction collaborative issues summarized above. Figure 2 depicts our process for identifying these factors. Initially, we conducted a literature search on the Web of Science and identified 15 highly relevant publications on collaborative design and construction management in railway EPC projects [33]. We then refined our findings by analyzing data from the Hangshaotai Railway, Yantong Railway, and Yangda Railway. In the next step, we invited 10 experts to participate in interviews, which helped to sort out the influencing factors and construct a preliminary list. Using the Wuli–Shili–Renli (WSR) methodology, we categorized these factors into three dimensions: the physics layer, affairs layer, and human layer, to form a framework system. We then conducted a questionnaire to determine the importance of each factor. A total of 102 questionnaires were distributed, and based on our findings, we revised the list of influencing factors. Ultimately, we identified 15 key factors that play a crucial role in collaborative design and construction management in railway EPC projects.

Finally, on the basis of finding the core elements, a questionnaire was used to determine the influence relationship between each factor and build a core element network. The questionnaire was distributed by e-mail and a total of 20 experts were invited to complete the questionnaire. These experts came from design units, construction units and professional colleges. They had professional knowledge of railway EPC projects, rich experience, and were willing to provide assistance for this research. Expert personal information statistics are shown in

Table 2. Information of experts.

Enterprise Type	Department	Level of Understanding of Railway EPC Projects	Years of Work Experience	Number of Experts
Design units	General contracting department	Very familiar	>10 years	3
Design units	General contracting department	Quite familiar	>10 years	5
Design units	General contracting department	Quite familiar	3–10 years	1
Construction units	Engineering department	Quite familiar	>10 years	2
Construction units	Metrology and compliance department	Quite familiar	>10 years	4
Construction units	Metrology and compliance department	Very familiar	>10 years	3
Professional colleges	Department of Engineering Management	Quite familiar	>10 years	2

.

2.2. Analysis of Design and Construction Coordination Problems

After expert interviews, as shown in Table 1, the existing problems can be summarized into four categories, namely: design optimization problems; process coordination problems; resource coordination problems; organization and coordination problems. The following will explain these four types of problems in detail.

2.2.1. Design Optimization Problems

First, inadequate consideration of constructability in the design resulted in drawings that did not meet on-site construction requirements, leading to delays, cost overruns and overall lack of control over project investment [34]. Insufficient assessment of the design’s impact on the later construction phase impeded collaborative management, hindering achievement of project objectives.

Second, the subcontractor’s willingness to participate in optimizing the design is low. While the general contractor of the railway may not be as experienced as the subcontractor who has been on the front line, they both share the responsibility of ensuring that the most reasonable plan is executed. In the event that the general contractor’s design plan is not optimized, the subcontractor is expected to provide sensible suggestions based on site conditions [35]. This is essential for the general contractor to amass project experience. Unfortunately, the lack of corresponding incentives means that subcontractors cannot be guaranteed of their interests after proposing an optimization plan. Consequently, subcontractors prioritize maximizing profits for themselves and do not remain united with the general contractor. This disunity leads to an unwillingness to invest manpower and material resources in optimizing the design. As a result, the value of design–construction integration remains unrealized.

Third, the low adoption of subcontractors’ optimization suggestions. In the EPC general contracting mode of railway construction projects, the construction map design and construction organization design should undergo joint evaluation and reasonable optimization by the general contractor design unit and the subcontractor construction unit. This breaks from the traditional design–bid–build (DBB) mode, where design and construction are separately managed, allowing for better design suitability to the actual site conditions. However, the design optimization process is currently unclear, and there exists a lack of trust between the general contractor and construction units, resulting in a lack of consideration for the optimization suggestions put forth by the construction unit, subsequently diminishing the construction unit’s enthusiasm.

2.2.2. Process Coordination Problems

First, the progress of design and construction is not in sync. In EPC mode, design and construction are carried out simultaneously but in stages. While this can accelerate the construction process, it requires good overlap between design and construction progress. However, railway EPC projects have long construction periods, complex working environments, changing owner needs and construction standards, and unclear interfaces which can impede design progress [36]. Drawings may not be approved on time, and design reviews and progress may lag behind, leading to difficulties in design management. Insufficient coordination between design and construction, a lack of timely design drawings, and inadequate cooperation with general contractors during the Yantong Railway’s construction exacerbated the issue. The general contractor was repeatedly asked to speed up the supply of design drawings and supplement resources to facilitate construction. The problems mostly arose due to discrepancies between the actual construction conditions and the initial survey [37], resulting in inconsistencies in the drawings, problems in the construction plan, or new requirements from the operating unit and facilities management unit. However, the design and redrawing process was slow, delaying the construction timeline.

Second, the level of information integration is suboptimal. While BIM technology has been implemented in railway construction projects to develop innovative project management techniques [38], the interconnectivity between different organizations remains inadequate. Each party has its own information management system, such as the owner unit’s digital construction management platform, and the general contractors’ internal BIM system, digital management system, and engineering intelligent building supervision platform. Nevertheless, all parties’ information management systems have not been adequately linked, often leading to separate and redundant platform functions and convoluted data. The absence of a unified collaborative management platform for information has hindered effective data transmission and integration, causing some roadblocks to collaborative design and construction management.

2.2.3. Resource Coordination Problems

First, insufficient engagement with subcontractors during the preliminary design phase. In the traditional railway DBB construction approach, the owner signed contracts with the design company and the construction company respectively. In contrast, with the Engineering, Procurement, and Construction (EPC) general contracting mode, the general contractor signs a contract with the construction unit and then delegates part of the project within the agreement to qualified subcontractors in compliance with the regulations, before signing subcontracts with them. During the bidding stage, which is also the critical preparatory phase, the general contractor cannot determine the construction unit during the project implementation stage, leading to a lack of shared interests and communication barriers between the two entities. The contractor’s comprehension, design methodology, and technical approach mostly rely on the conventional design institution management system, overlooking the actual situation of the construction team and failing to optimize the design correctly or achieve true integration of design and construction. In early decision making, subcontractor involvement is inadequate [39], resulting in weak coordination between design and construction, lack of coherence, joint scheme optimization, construction map customization, budget estimate preparation, equipment and material selection, and progress management.

Second, low willingness to collaborate on and adhere to construction drawings. Initially, designers were solely responsible for full-time design work and the production of drawings in accordance with specifications. However, their participation in the general contracting project resulted in difficulty and resistance. Designers lacked a deep understanding of the project’s general contracting mode and failed to ideologically improve their awareness of design services.

Third, the subcontractor’s knowledge sharing [40] is inadequate. While they are responsible for constructing according to the design plans offered by the design team, they occasionally fail to notify the general contractor when they identify flaws in the designs. This lack of communication and collaboration can negatively impact project quality and cause issues during the acceptance audit phase. The subcontractor’s reluctance to follow the construction drawings provided by the general contractor increases the challenge faced by the design team [41], who serve as the general contractor for this railway EPC project, as they strive to manage the collaboration of design and construction processes effectively.

2.2.4. Organizational Coordination Problems

First, inadequate staffing is an issue when it comes to general contractors for railway construction projects. Typically, these contractors rely on developing project management staff in-house. Upon receiving a project, some designers are assigned to manage the EPC project, and human resources are added incrementally through a “temporary team” approach. In the design institute, professional and technical personnel serve as the backbone of the business. However, some of the professional design leaders are overburdened by multiple railway design tasks, and are not present on the project site. This results in ineffective communication [42], untimely problem solving, and poor design coordination for the construction phase.

Second, inadequate personnel experience is hindering the expansion of EPC general contracting projects in railway design units. The existing full-time on-site management personnel lack sufficient understanding of on-site construction protocols [43], EPC project management, and on-site construction management experience. Moreover, project managers lack practical experience, and do not possess the requisite comprehensive qualities that respond to the demands of EPC projects. The design unit also lacks project management abilities and experience, thereby failing to guide the work management of subcontractors during project implementation. Overreliance on subcontractors for on-site project management risks transferring construction work erratically, while escrow management practices do not fully harness the advantages of design and construction integration.

Third, the project management interface lacks coordination. Railway engineering general contracting projects require corresponding professional personnel to be incorporated into the project management, but the lack of coordinated division of labor results in unclear responsibilities and an uncoordinated project management interface [44], hindering interaction between design and construction. Although a cooperative and trusting relationship should be established between the general contractor and subcontractors, the long-standing opportunism and lack of vertical cooperation in subcontracting practices often leads to tense and antagonistic relationships. Within the framework of subcontracting, the general contractor tends to adhere to traditional management thinking, resulting in unclear communication and coordination at the management level. Since subcontractors have a lower position in the overall organizational structure and encounter too many higher-level units for docking, their requirements are not unified. Conflicts arise when instructions issued by different parties are contradictory, and subcontractors lack the motivation to promote the integration of design and construction.

2.3. Identification of Core Elements

This research employs the WSR methodology to ensure the accurate identification of influencing factors. Developed by Gu Jifa and Zhu Zhichang [45,46], WSR is a comprehensive management approach. “Wuli” pertains to the objective truth of existence and change. “Shili” denotes the methods and techniques for managing organizations and tasks, while “Renli” addresses human needs and pursuit.

Harold Linstone, former president of the International Society for Systems Science (ISSS), classified WSR as a representative of the multidimensional system management model in 1999. Currently, the ISSS website lists WSR, along with TOP, MMD, and TSI, under the “meta-methodology” section. WSR is typically discussed in the fields of knowledge management, strategic management, and Eastern systems methodology. It is also used in specific areas, such as evaluating building energy management, manufacturing enterprises, manufacturing energy intensity impact factors, and measuring software complexity. Notably, Bolisani and Bratianu [47] compared WSR with the “strategy as practice” (SAP) approach in strategic research, highlighting both methods’ focus on people’s interaction in practice. Denis Caro [48] noted that there is a certain correlation between WSR and grounded theory. Pillet M et al. [49] used WSR to establish a set of methods, processes, and mechanisms for implementing continuous management improvement in the international “Cartier Tabulation”. Professor Cathal M. Brugha of University College Dublin, Ireland, has shown a keen interest in WSR methodology [50]. By comparing WSR with his own CmCvAwAs system theory (committing-convincing-adjusting world-adjusting self), he found that the three core dimensions of his theory—adjusting, convincing, and committing—correspond to Wuli, Shili, and Renli, respectively [51]. He suggests that there may be common structures in cross-cultural and cross-domain thinking and decision-making processes.

Multi-Modal System Design (MMD) is an approach to social system design that combines technology and humanities in a theoretical framework [52]. Similar to WSR methodology, it emphasizes a holistic view and humanistic care, but its unique module levels may limit its ability to capture high-level conceptual information. Total Systems Intervention (TSI) was developed by Flood and Jackson in 1991 to help practical managers apply “critical systems thinking” principles in three stages: creativity, choice, and implementation [53]. While it shares some similarities with WSR in selecting appropriate problem solutions, TSI has a wider application scope. In summary, WSR integrates objective laws and humanistic care, TOP integrates technology and society, MMD reflects an ecological system view combining technology and humanities, and TSI integrates both wisdom and technology in a practical approach.

Collaborative management of railway EPC project design and construction is a complex systemic challenge. In tackling such complex problems, the WSR methodology provides an effective system analysis tool. The approach emphasizes the need to consider objective laws, mechanisms, and management theory, while also taking into account the subjective initiative of organizations and individuals. This allows for a systematic, comprehensive, and hierarchical study of problems. The following will introduce the three types of factors of Wuli, Shili, and Renli in detail.

2.3.1. Core Elements of Physics

“Wuli”, that is physics, refers to the objective conditions and resources that involve the substances and their mechanisms in complex systems. This encompasses not only physics in its narrow sense, but also chemistry, biology, geography, and astronomy. It represents an objective and real knowledge that explains the internal mechanisms of existing things. In this study, “physics” mainly refers to the technical environment, encompassing not just the technical skills of the participating units but also the application of information technology tools such as BIM [54]. The term “objective environment” primarily encompasses external force majeure factors, including natural and social environment, policy, and legal factors.

2.3.2. Core Elements of Affairs

“Shili”, that is affairs, pertains to the reality of engaging in activities, and the challenge of making decisions that optimize stakeholder benefits needs to be addressed. The objective of “Affairs” is to establish a functional framework for stakeholders to resolve issues. The process should fully utilize human expertise, knowledge, and provide decision-making support. The “Affairs” discussed in this study primarily refers to the operating mechanism, which encompasses the practical experiences and guarantee mechanisms required for the effective collaboration between design and construction firms. Practical experiences cover the standard procedures, tools, techniques, and processes utilized in daily operations, while guarantee mechanisms include communication and coordination processes, risk-sharing mechanisms, and overall collaborative management procedures that regulate the equitable distribution of rights, responsibilities, and benefits between design and construction firms.

2.3.3. Core Elements of Human

“Renli”, that is human, encompasses the essence of being a human being and depends on knowledge from humanities, social sciences, and related fields to conduct multidimensional analyses of human behavior. Subjective behavior and consciousness are typically complex, and psychology, behavior, value orientation, worldview, culture, beliefs, religion, and emotions all impact thoughts and behaviors, leading to complex social activities involving people as the main subject. In this study, “human” mainly refers to the ideas, attitudes, and cognition of design and construction organizations to analyze methods for enhancing collaborative enthusiasm and maturity, and ultimately, improving collaborative management performance. Examples of such methods include incentive and restraint mechanisms, and trust [55] and reciprocity mechanisms, among others.

The core elements of the design–construction coordination mechanism are shown in

Table 3. Core elements of design–construction coordination mechanism.

Dimension	Core Element	Element Explanation
Physics (Wuli)	Information-sharing platform	Railway information technology drives innovation and development, project management systems of design units and construction units are interconnected, and management platform integration improves work efficiency.
	Design and construction technology level	The design and construction of its own hard power, including the maturity of technology and technology, advanced technology and equipment, etc. If the construction unit cannot fully understand the design intent and technical difficulties, may cause design changes in the construction stage.
	Project Social Environment	Market and industry environment of Railway EPC Projects.
	Standard specification system	A complete standard system established within the organization.
	Project size and complexity	Projects vary in size and complexity.
Affairs (Shili)	Collaborative management process	In practice, a complete collaborative management process has been formed.
	Design management system	Design disclosure and joint review of drawings: The designer should fully convey the technical difficulties and design concepts to the constructor, and, at the same time, the constructor should put forward reasonable suggestions to ensure the constructability of the design drawings; reasonableness of bid division: greatly shorten the construction period and realize “Design while construction”; the efficiency of designing drawings and the response efficiency of Motion Design changes on the construction site.
	Interface management system	Project interface management: Whether the rights, responsibilities and interests of all parties in the design and construction are clearly defined.
	Risk-sharing mechanisms	The risk-sharing and sharing management system for design and construction in the face of risk events; whether the pricing method stipulated in the design and construction contract meets the reasonable risk-sharing requirements.
	Coordination and communication mechanism	Whether the communication between all parties is smooth, whether the collaborative work and other processes are smooth.
Human (Renli)	Relationship quality	The quality of communication and mutual understanding between partners.
	Personnel attitude and experience	Attitude and cognition of design and construction personnel towards collaborative management; traditional thinking mode and design concept.
	Organization building	Collaborative work, organizational structure, team building, collaborative management ability of internal personnel.
	Owner’s support	External support, motivation and drive of the owner.
	Incentive constraint mechanism	Whether there are workable incentive and restraint schemes, means and processes within the design and construction unit.

.

2.4. Construction of Relational Network Structure

This study aims to further analyze the relationship between the core elements of the design and construction coordination mechanism of railway EPC projects. A questionnaire was compiled to assess the strength of the relationship between the 15 core elements. Experts were surveyed using the expert survey method to assign directed relationship data that represented the relationship between element nodes. The influence degree of X factor on Y factor is divided into 5 levels: no relationship, weak relationship, medium relationship, strong relationship, and very strong relationship, based on expert assessments corresponding to scores 1–5. Research includes experts from universities and scientific research institutes, as well as engineers in the field of railway engineering construction. By examining the relationship between the core elements and their strength, a more complete understanding of the design and construction coordination mechanism of railway EPC projects can be obtained.

The arithmetic average value is used to synthesize expert feedback and establish an assignment-directed matrix of relationship strength for the core elements of the railway EPC project design and construction coordination mechanism. This is shown in

Table 4. Relationship intensity matrix of core elements of design–construction coordination mechanism.

Core Element	Code	F1	F2	F3	F4	F5	F6	F7	F8	F9	F10	F11	F12	F13	F14	F15
Information-sharing platform	F1	/	1.50	1.21	3.74	1.72	4.21	3.66	4.51	2.00	4.87	4.31	2.45	4.29	1.06	3.21
Design and construction technology level	F2	3.46	/	1.02	3.50	1.04	4.35	4.46	3.03	4.44	1.81	3.90	2.79	3.12	1.98	4.08
Project social environment	F3	2.66	2.34	/	3.91	3.99	2.92	2.98	3.60	2.87	3.55	2.71	2.09	4.10	3.12	3.51
Standard specification system	F4	4.01	2.51	1.08	/	2.38	4.52	3.70	4.53	3.79	4.67	3.99	3.20	4.27	1.20	3.01
Project size and complexity	F5	3.29	2.56	2.03	4.29	/	4.40	4.37	4.53	4.00	4.28	3.25	2.39	4.11	2.80	3.24
Collaborative management process	F6	4.05	1.28	1.30	3.77	1.25	/	4.11	3.99	3.41	4.88	3.59	3.20	2.93	1.68	3.56
Design management system	F7	4.30	2.02	1.26	2.89	1.09	4.26	/	3.89	2.38	4.20	3.48	2.41	2.33	1.29	4.47
Interface management system	F8	3.43	1.67	1.80	3.00	1.35	3.77	3.90	/	3.12	4.71	3.82	3.93	4.01	1.00	2.38
Risk-sharing mechanisms	F9	1.34	1.40	1.11	4.09	2.31	3.16	4.25	4.60	/	4.00	3.21	4.09	4.28	3.10	4.32
Coordination and communication mechanism	F10	3.61	1.22	1.28	3.17	1.20	4.53	3.00	4.44	2.65	/	3.77	2.60	4.11	2.02	3.23
Relationship quality	F11	3.20	1.00	2.00	4.03	1.18	3.51	2.19	3.82	3.89	3.90	/	4.33	3.76	2.30	3.69
Personnel attitude and experience	F12	3.90	1.36	1.27	3.45	3.47	4.11	2.82	3.59	3.40	4.48	4.67	/	4.13	3.22	3.94
Organization building	F13	3.58	3.05	1.00	4.61	2.64	4.50	3.87	4.08	3.81	4.22	4.25	4.21	/	3.69	3.22
Owner’s support	F14	3.88	1.81	4.09	3.21	3.04	3.49	4.02	4.17	4.36	4.59	2.48	4.81	4.39	/	3.55
Incentive constraint mechanism	F15	2.10	2.99	2.48	2.31	1.42	3.06	4.20	3.77	3.90	4.21	4.49	4.60	4.08	2.32	/

. The NetDraw mapping tool is used to construct a network diagram illustrating the relationships between these core elements, as depicted in Figure 3. The graph shows that the core elements are closely interrelated. Network density, cohesive subgroups, centrality, and structural voids were analyzed using UCINET 6.0 software. This allows us to investigate the relationships between the core elements of the design and construction coordination mechanism at both the network population and individual level.

After finding the problem, analyzing the reasons, and constructing a network of influencing factors, the following is further analyzed using the SNA method.

3. Results and Analysis

The social network diagram for the coordination mechanism of railway EPC project design and construction depicts a highly interdependent relationship between the core elements. The social network analysis method employs evaluation indicators that can be categorized into overall network indicators and individual network indicators [56]. The former pertain to the analysis of all nodes contained within the social network and their relationships, and typically include network density and path length. Conversely, the latter relate to an individual node as the central point and the network formed by its direct relationships. Degree centrality, betweenness centrality, and closeness centrality are some commonly used analysis techniques for individual network indicators. Through network analysis, we found that the relationship network structure of core elements in railway EPC project coordination is stable. Coordination and communication mechanisms, organization building, interface management systems, and design management systems are critical components that impact collaborative performance.

3.1. Analysis of Overall Network Properties

3.1.1. Analysis of Network Density

Social network density refers to the proportion of actual connections in a network graph compared to the maximum number of potential connections. It is used to indicate the degree of closeness between nodes within a social network. In the context of the multi-valued directed relationship strength matrix described in this paper, network density is calculated using the formula: Density = K/[N × (N − 1)], where N represents the number of network nodes and K represents the total value of arrows in the graph. Higher values of social network density reflect stronger relationships between network nodes and greater overall cohesion of the network.

After analyzing the network density through the use of UCINET 6.0 software, it was determined that the design and construction coordination mechanism in railway EPC projects had an overall network density of 3.2083, with a standard deviation of 1.0967. This finding suggests that the network connectivity among the core elements of the design and construction coordination mechanism is highly dense, indicating a strong and interconnected relationship between various elements. Even the slightest change in any two core elements within the network could lead to a significant alteration of the overall network structure. The analysis of network density has revealed that the coupling interaction among the core elements can impact the design and construction coordination mechanism and the collaborative management structure of railway EPC projects. These changes may create practical issues in the collaborative management of railway EPC projects, ultimately negatively impacting their performance.

3.1.2. Analysis of Condensed Subgroups

The cohesion subgroup is composed of multiple elements that have relatively strong, direct, and close connections, which reflect the real or potential relationship between each element. By analyzing condensed subgroups, it is possible to identify subgroups that closely interact with each other, known as the “substructures” found within the relationship network. This type of analysis provides a more comprehensive understanding of the overall structure of the railway EPC project design and construction coordination mechanism.

Condensed subgroup analysis algorithms are classified into four types: those based on reciprocity, where typical algorithms have factions; those based on accessibility and diameter, where typical algorithms have N factions; those based on point degrees, where typical algorithms have K bundles and K cores; and those based on the relationship between internal and external subgroups, where typical algorithms have K bundles and K cores. CONCOR provides the following two benefits over other algorithms: (1) it is more flexible since it is based on conditional judgment; (2) there will be no boundary randomization problem, and the mined factor clusters are more in line with the actual situation.

To perform the condensed subgroup analysis, the CONCOR method in UCINET 6.0 software was used, and the results are shown in Figure 4. The overall relationship network structure among the core elements of the railway EPC project design and construction coordination mechanism is relatively stable and is composed of four sub-groups: “Information-sharing platform—Interface management system—Coordination and communication mechanism—Standard specification system”, “Relationship quality—Collaborative management process—Design management system,” “Risk-sharing mechanisms—Personnel attitude and experience”, and “Project social environment—Project size and complexity”. These internal elements frequently interact with each other, forming a closely linked network. Furthermore, the addition of elements such as the incentive constraint mechanism, organization building, design technology level, construction technology level, and owner’s support enhances the efficiency of coordination and interaction between different groups. These elements create a dynamic network of “intra-group communication and inter-group interaction”.

3.2. Analysis of Individual Network Attributes

3.2.1. Analysis of Centrality

Centrality refers to the position of a node in the core of a network. To analyze centrality, three indicators are commonly used: degree centrality, betweenness centrality and closeness centrality. This study uses UCINET6.0 software to analyze each node’s centrality indices, which are presented in

Table 5. Centrality of core elements of relationship networks.

	Degree Centrality (Out-Degree)	Degree Centrality (In-Degree)	Betweenness Centrality	Closeness Centrality (In-Closeness)	Closeness Centrality (Out-Closeness)
Information-sharing platform	52.9	77.43	6.83	44.57	48
Design and construction technology level	47.19	69.07	4.95	20.1	42.86
Project social environment	45.35	66.38	3.92	19.21	42.86
Standard specification system	55.53	81.28	7.15	92.31	83.33
Project size and complexity	51.41	75.25	4.16	44.57	48
Collaborative management process	55.97	81.92	7.48	92.31	100
Design management system	56.63	82.89	6.65	100	100
Interface management system	57.4	84.02	9.78	100	100
Risk-sharing mechanisms	54.92	80.39	7.29	66.67	83.33
Coordination and communication mechanism	60.22	88.14	7.85	100	100
Relationship quality	55.39	81.07	6.86	92.31	83.33
Personnel attitude and experience	53.25	77.94	7.17	63.16	48
Organization building	58.21	85.2	8.15	100	100
Owner’s support	51.67	75.63	5.23	63.16	48
Incentive constraint mechanism	54.1	79.19	6.39	48	83.33

. The point degree centrality index shows that the coordination and communication mechanism, organization building, interface management system, design management system, and collaborative management process have the maximum standard outward point degree centrality (>55.5%), and these five nodes directly point to the largest number of other element nodes. The coordination and communication mechanism, organization building, interface management system, and design management system have the maximum standard inward point centrality (>82.8%), and the other nodes directly point to the largest sum of these four elements. By combining the analysis of outbound and inbound centrality, it can be concluded that the coordination and communication mechanism, organization building, interface management system, and design management system are the core elements of the network, and they interact most frequently with other elements. These elements affect and drive each other, and contribute to the effectiveness of collaborative management in railway EPC project design and construction. Therefore, it is crucial to pay attention to these latent variables during the collaborative management process.

The Closeness Centrality Index highlights that the coordination and communication mechanism, organization building, interface management system, and design management system are the most important elements in railway EPC project design and construction coordination, with an inward closeness centrality of 100%. This suggests that these elements are not significantly influenced by resource inputs and remain undeterred by other elements. Similarly, the coordination and communication mechanism, organization building, interface management system, design management system, and collaborative management process have an outward closeness centrality of 100%, indicating that they are less reliant on other elements for resource output. Meanwhile, the betweenness centrality index analysis reveals that none of the core elements in the three dimensions are significant enough to control other elements completely. Thus, the mutual control effect between these core elements is weak, implying that the collaborative management of railway EPC project design and construction is a complex and interrelated network. The study also found that while the interface management system (9.78%) and organization building (8.15%) have relatively higher betweenness centrality than others, they cannot fully control other elements of the network. This result shows that the collaborative management of railway EPC project design and construction is a holistic governance network composed of the physics dimension, affairs dimension and humans dimension, and it is difficult to effectively regulate the project using conventional management methods.

The analysis of the degree centrality, betweenness centrality, and closeness centrality indicators reveals that the coordination and communication mechanism, organization building, interface management system, and design management system form the core element relationship network in the railway EPC project’s design and construction coordination mechanism. These elements’ core position within the network structure enables them to have a significant impact on the overall system’s functioning. The coordination and communication mechanism is not only the core of the matter dimension, but also the central node of the network of all elements. This element maximizes the synergies between design and construction, thereby ensuring that the railway EPC construction project progresses in a timely and efficient manner. On the contrary, the project social environment, design and construction technology level, and project size and complexity have little influence on the relationship network of elements of the design and construction coordination mechanism of railway EPC projects. These elements are weak and unimportant for the project’s overall functioning. Optimizing the collaborative management structure can provide an important auxiliary role in the development of the railway EPC project. The optimized structure can enhance the project’s overall efficiency by streamlining the coordination and communication mechanism, the organization building, interface management system, and design management system. The optimized management structure can also help mitigate any potential difficulties that could come up during construction, thereby enhancing the project’s success.

3.2.2. Analysis of Structural Hole

Structure hole is a phenomenon in which one element in a social network is directly related to some elements, but not directly related to other elements. This phenomenon is indicative of non-redundant connections among the elements. The Bert structure hole index is a rich and effective metric for measuring this phenomenon, and it has been selected for use in this paper.

Table 6. Redundancy of core elements.

Core Element	Code	F1	F2	F3	F4	F5	F6	F7	F8	F9	F10	F11	F12	F13	F14	F15
Information-sharing platform	F1	0	0.61	0.61	0.72	0.61	0.83	0.72	0.83	0.61	0.83	0.72	0.72	0.83	0.61	0.72
Design and construction technology level	F2	0.72	0	0.61	0.72	0.61	0.72	0.83	0.72	0.72	0.61	0.72	0.72	0.83	0.61	0.83
Project social environment	F3	0.72	0.61	0	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.83	0.72
Standard specification system	F4	0.72	0.61	0.61	0	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.83	0.61	0.72
Project size and complexity	F5	0.72	0.61	0.72	0.72	0	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.83	0.72	0.72
Collaborative management process	F6	0.72	0.61	0.61	0.72	0.61	0	0.72	0.72	0.72	0.83	0.72	0.72	0.72	0.61	0.72
Design management system	F7	0.72	0.61	0.61	0.72	0.61	0.83	0	0.72	0.72	0.72	0.72	0.72	0.72	0.61	0.83
Interface management system	F8	0.72	0.61	0.61	0.72	0.61	0.72	0.72	0	0.72	0.83	0.72	0.72	0.83	0.61	0.72
Risk-sharing mechanisms	F9	0.61	0.61	0.61	0.72	0.72	0.72	0.72	0.72	0	0.72	0.72	0.72	0.83	0.72	0.72
Coordination and communication mechanism	F10	0.72	0.61	0.61	0.72	0.61	0.83	0.72	0.83	0.72	0	0.72	0.72	0.83	0.72	0.72
Relationship quality	F11	0.72	0.61	0.61	0.72	0.61	0.72	0.72	0.72	0.72	0.72	0	0.83	0.83	0.61	0.72
Personnel attitude and experience	F12	0.72	0.61	0.61	0.72	0.61	0.72	0.72	0.72	0.72	0.72	0.83	0	0.83	0.72	0.72
Organization building	F13	0.72	0.61	0.61	0.72	0.61	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0	0.72	0.72
Owner’s support	F14	0.72	0.61	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.83	0.83	0	0.72
Incentive constraint mechanism	F15	0.72	0.61	0.61	0.72	0.61	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0

presents redundancy analysis results for the investigated elements. The results demonstrate relationships between information-sharing platforms and collaborative management processes, collaborative management processes and design management systems, personnel attitudes, experiences and organizational development, design and construction technology levels, and incentive constraint mechanisms. These relationships exhibit significant levels of redundancy, with 87% of adjacent elements having direct links to other elements. Consequently, there are fewer interruptions or delays in interactive information exchange within the network.

Based on the results of the analysis of the Structural Hole Index provided in

Table 7. Analysis of the core element relationship network structure hole.

Analysis of Structural Holes	Effective Size	Efficiency	Constrain	Hierarchy
Information-sharing platform	3.769	0.269	0.274	0.024
Design and construction technology level	3.627	0.259	0.276	0.017
Project social environment	3.792	0.271	0.274	0.009
Standard specification system	3.944	0.282	0.269	0.015
Project size and complexity	3.830	0.274	0.273	0.012
Collaborative management process	3.859	0.276	0.270	0.017
Design management system	3.926	0.280	0.270	0.014
Interface management system	3.912	0.279	0.269	0.016
Risk-sharing mechanisms	3.970	0.284	0.270	0.016
Coordination and communication mechanism	3.926	0.280	0.269	0.017
Relationship quality	3.925	0.280	0.270	0.016
Personnel attitude and experience	3.804	0.272	0.272	0.021
Organization building	4.121	0.294	0.266	0.011
Owner’s support	3.639	0.260	0.276	0.023
Incentive constraint mechanism	4.021	0.287	0.268	0.013

, it appears that the organization building element has the largest size (4.121), the highest efficiency (0.294), and the lowest limitation system (0.266). These statistics suggest that organization building plays an integral role in the network, occupying the most structural holes. As a result, it has a more significant control ability over other network elements. In contrast, the design and construction technology element has the smallest size (3.627), the lowest efficiency (0.259), and the highest degree of restriction (0.276), with a relatively small degree of hierarchy (0.017). This suggests that design and construction technology is easily influenced and controlled by other elements, making it difficult for it to play the core role it is meant to. The results of the structural hole analysis also demonstrate that design and construction technology is weaker in the relationship network than other core elements within the design and construction coordination mechanism of railway EPC projects. As such, improvements to design and construction synergy can only be made through better coordination with other elements. To leverage the synergistic effect of railway EPC project design and construction, it will be essential to construct an organizational structure at the core position of the core element relationship network of the coordination mechanism.

4. Discussion and Conclusions

This study focuses on collaborative management of design and construction in railway EPC projects. By conducting a literature research, case studies, and expert interviews, the current state of collaborative management in these projects is analyzed, identifying a list of influencing factors that affect design and construction management. To construct the coordination mechanism of design and construction in railway EPC projects, a relationship network based on WSR is established. Social network analysis is employed to examine the relationship network structure and the strength of relationships among core elements.

Upon analyzing the results, several conclusions can be drawn regarding the design and construction coordination mechanism in railway EPC projects. First, there is a high correlation and dependence between the core elements of this mechanism. This suggests that project management involves multiple elements interacting with each other, rather than a single, dominant process. Second, the overall relationship network structure of the core elements is relatively stable, forming four condensed subgroups. These subgroups include “information-sharing platform—interface management system—coordination and communication mechanism—standard specification system”, “relationship quality—collaborative management process—design management system”, “risk-sharing mechanisms—personnel attitude and experience”, “project social environment—project size and complexity”. Third, certain elements such as the coordination and communication mechanism, organization building, interface management system, and design management system have more influence in the network than others like project social environment or project size and complexity. Of these, the coordination and communication mechanism plays the most critical role, as it not only determines the synergistic effect of project design and construction, but also plays a crucial role in the connection and wider scope of human and physical mechanisms. Lastly, while the core elements are interdependent and drive each other, no single element can fully control the others, and the overall design and construction coordination mechanism cannot be separated from other elements. Mutual assistance and support are crucial in ensuring the success of railway EPC projects.

To address the practical issues surrounding the coordination of railway EPC projects in China, it is essential to enhance the existing design and construction coordination mechanism while balancing the power dynamics between the three parties of humanity, physics and affairs. Additionally, it is crucial to establish a clear understanding of the interaction between the core elements and to strengthen these relationships to form an effective network capable of supporting a coordinated mechanism for EPC projects within the railway industry. Based on the research findings, it is recommended that collaborative management of railway EPC project design and construction focus on human-, physical-, and affair-related factors. By doing this, the railway EPC project design and construction coordination can be aligned with the specific demands and challenges within the Chinese context. Drawing from research findings and expert experience, we provide recommendations from three angles: “Renli”, “Shili”, and “Wuli”. Our team learned during investigations and interviews with other projects that these suggestions have been successfully applied to the Shantou–Shanwei Railway project. This high-speed railway, using the EPC construction management model, is expected to open in 2023. Notably, the implementation of a tripartite joint meeting system, a standardized process system and an intelligent information management platform helped to efficiently tackle challenges in design optimization, organization coordination, resource collaboration, and process collaboration.

Three suggestions are put forward from the perspective of “human”: (1) By establishing a subcontractor management system, develop long-term strategic cooperative partnerships [57]. The general contractor updates the subcontractor information in the database according to the process control records, establishes a comprehensive credit evaluation and evaluation system for subcontractors exclusive to the general contractor enterprise, and continuously improves the subcontractor management database to provide guidance for the selection of cooperative subcontractors for subsequent projects. (2) In order to fully mobilize the enthusiasm of subcontractors, establish a reasonable incentive and restraint mechanism. Encourage subcontractors to make suggestions on design optimization, construction optimization and rationalization, and encourage them to propose technical solutions to promote innovation, consider design layer bonuses, or optimize revenue sharing. In the whole process of project construction, in order to ensure the construction period, quality, and safety, the general contractor also needs to establish an assessment mechanism, strengthen the review of the subcontractor management system, and check the implementation of the management system. (3) Strengthen the construction of the general contracting project organization. The railway EPC project should adopt a strong matrix organization and management model. All parties should transfer project managers to jointly establish the project department, and, at the same time, grant the project manager sufficient management authority, so that while playing the role of organization and coordination, it can play the role of leading decision making. The training of general contracting project managers is more complicated than the traditional survey and design talent training process, and the management requirements are higher. Top-level design should be conducted well, and general contracting project management personnel training methods should be formulated. Appropriate incentive measures can be taken to encourage designers to participate in general contracting project management. Cultivate compound talents who understand design, construction and procurement and have experience in the whole process management of general contracting projects.

Two suggestions are put forward from the “affairs” dimension: (1) Establish an effective coordination and communication mechanism. In the early stage of a railway construction project, a joint leading group should be established jointly with the construction unit, the general contractor unit, the construction unit, the supervision unit, the operation unit, etc., and the participating parties should clarify the project coordination mechanism and decision-making mechanism, strengthen communication and coordination, and improve the efficiency of project decision making. The general contractor may establish a special regular coordination meeting system, communicate with each subcontractor unit and supervision unit in a timely manner, and hold regular coordination meetings to promote the formation of a community of interests by all parties. The general contractor shall actively communicate with all subcontractors, do a good job in the disclosure of drawings, accurately convey the design concept of the design scheme to the subcontractors, and discuss the disagreements in the design scheme to ensure the feasibility and accuracy of the design scheme. (2) Improve the design and construction collaborative management system and risk-sharing mechanism. To incorporate the control of design nodes into the project planning and monitoring system, especially for the key links with a long construction period, the time of each node in all links must be clearly formulated in detail, and the relevant units must strictly follow the regulations. This can not only ensure the integration of the entire design and construction, but also effectively shorten the construction period. To be responsible for the completeness and standardization of drawings, pay attention to the constructability of design, improve design quality, ensure the effective connection between design and construction, and achieve the overall quality goal of the project. In the design stage, the cost required for the design of each link should be taken into account in the EPC cost management system. In addition, the design changes of railway construction projects under the EPC general contracting mode should give full play to the advantages of deep integration of design and construction, achieve rapid response, refine and deepen the design, and effectively solve the pain points and difficult problems on site to ensure that the overall promotion efficiency of the project is improved.

Two suggestions are put forward from the “physics” dimension: (1) Improve the relevant rules and regulations of the railway EPC general contracting mode, promote the standardized development of EPC general contracting mode for railway projects; conduct construction project bidding, engineering construction contracting, contract management, qualification and qualification supervision, engineering supervision, drawing review, quality and safety, completion acceptance, engineering audit; other core systems shall be appropriately revised and adjusted; and the legal status, responsibilities and authority, interface division, interface management, management logic relationship, risk-sharing scope and content of each participating party in the EPC project shall be clarified, so as to improve the project management mechanism, management norms, management processes and related management systems of the EPC general contracting model. The EPC project management level of the general contractor provides a good policy environment. (2) Strengthen the construction of the design and construction information collaborative management platform [58]. All parties involved in the construction need to jointly use information technology such as BIM, Internet of Things, GIS, etc., establish an information collaborative management platform, and share information such as engineering data [59], technical information, design documents and construction plans in a timely manner, which will help promote the integration of design and construction, improve construction efficiency and quality, and reduce costs.

However, this study still has some limitations. The aim of this research is to examine the key common elements and their interactive relationships within the coordination mechanism of railway EPC project design and construction from a macro perspective, and to address the challenges in the current governance practices of Chinese railway EPC projects. However, this research only focuses on railway EPC projects in China and does not consider the characteristics of such projects in other countries and regions. Moreover, this study does not classify the research according to different EPC management models, such as the “PPP + EPC” model or the “F + EPC” model, and the analysis process lacks a microscopic perspective. In addition, the implementation of the above suggestions in railway EPC projects has also encountered some obstacles, such as where the uncertainty of design optimization has a great impact on the income of the general contractor. The relevant laws and regulations are not perfect, resulting in the passive management of the general contractor. Although the constructability of drawings has been improved, it has not been fundamentally changed. Future studies will further refine the design–construction coordination mechanism by integrating findings from this research and practical cases of railway EPC projects. Additionally, other perspectives can be explored to understand the influencing factors of design–construction coordination. By utilizing the synergies, we can enhance the governance performance of railway EPC projects and fully leverage the benefits of the EPC construction mode.