Measurements and Analysis of Electromagnetic Compatibility of Railway Rolling Stock with Train Detection Systems Using Track Circuits

Abstract

One of the main challenges in the operation of electric traction vehicles is ensuring safety and operational reliability. To ensure the safety of railway traffic, vehicles must undergo a series of tests related to the investigation of disturbances generated, among others, in the return current to the mains. This problem is further complicated by the inability to perform such measurements under laboratory conditions. The implementation of tests under real conditions determines the appearance of additional potential interference sources, from power sources to improper interactions between current collectors and the overhead contact system, and it requires strict compliance with regulatory standards and the implementation of standardized testing procedures. This article presents issues related to the investigation and analysis of the electromagnetic compatibility of rolling stock with train detection systems using track circuits. The aim of these tests is to determine the harmonic components in the traction current in relation to the permissible levels specified in the latest editions of the European Railway Agency—ERA/ERTMS/033281 version 5.0 documents and Annex S-02 to the List of the President of the Office of Rail Transport. The measurement methodology and test procedures are presented in detail with respect to current legal requirements.

1. Introduction

The modern railway system can be thought of as a form of vast microgrid combining distributed active loads (trains), energy sources (renewable-based microgrids) and energy storage devices [1,2]. The drive to increase energy efficiency and reduce pollution in railroad systems is emphasized through the implementation of smart grid and microgrid concepts. Menicanti et al. present the use of a rail microgrid to recover energy from train braking and the charging infrastructure of electric vehicles [3]. Kaleybar et al. present the concept of smart hybrid rail microgrids (H-RMGs) integrating renewable energy sources, storage systems and electric vehicle charging stations into existing rail systems [4]. Electromagnetic interference (EMI) generated by rolling stock has the potential to affect components of the rail microgrid, such as energy control systems, power converters, storage systems and others. Midya et al. describe how EMI generated inside the rail system or originating from outside often disrupts the overall system performance and causes interference in nearby civil systems. The main sources of EMI in the rail system are the rolling stock (drives, brake systems, pantograph arcing), supply substations, environmental sources (e.g., lightning) and the track itself [5]. Traction rolling stock generates harmonics primarily resulting from the operation of converters. The converters of the currently produced locomotives and electric multiple units operate at frequencies in the range of 30 to 300 Hz. Static converters usually operate at frequencies of several kilohertz; hence the most important factor is the so-called switching noise in the range of 2–20 kHz. Occasionally, the factor influencing the generation of electromagnetic interference is the dynamics of the pantograph. However, this is subject to separate legal requirements, and its incorrect behavior is easier to detect during periodic inspections. Ensuring that the electromagnetic interference generated by these vehicles does not adversely affect the stability and safety of the microgrid and its control elements is an important aspect of planning and operating the microgrid.

The safety of railway traffic depends, among others, on the operational reliability of railway traffic control devices (RTCs) [6,7]. Their operation is influenced by many devices installed on the vehicles and within the trackside infrastructure [5,8]. Interference problems in railroad traffic control devices have been known for a long time [9]. Especially crucial is the risk of false occupancy of the track circuit, or rather its nonexistence, as well as signal malfunctions (the inability to detect a vehicle within the track segment). In recent years, with the use of an increasing number of electronic devices and power electronic converter systems, their size and variety have increased significantly, which is also reflected in the number of publications devoted to this topic [10,11,12]. The harmonic and impulse influences of the return traction current (especially on AC electrified railways) are the cause of a significant number of track circuit failures [13]. Paper [14] points out that a second-order passive filter can be an optimal solution for mitigating harmonic interference in railroad signaling equipment caused by traction harmonics. On the other hand, paper [15] notes that the use of surge protective devices and shielded incoming lines can effectively reduce the risks of lightning damage to railway traffic control systems. In general, electromagnetic interference generated unintentionally can adversely affect electronic protection systems, requiring technical and organizational measures to protect against it [16]. However, there is still a need to analyze interference due to the need to identify sources of it in order to eliminate them. This applies especially to interference currents with frequencies that coincide with the operating frequency of RTC devices [9,13,17]. Furthermore, with the increasing speed of railway vehicles resulting, among others, from the modernization of railway lines, the demand for the amount of energy supplied increases, leading to an increasingly higher power consumption [18,19]. Current harmonics present in the traction network directly affect infrastructure devices, particularly railway traffic control devices [20,21]. The research carried out so far on the level of disturbances generated by traction vehicles in the network confirms that innovative methods are required to identify factors that generate unfavorable harmonics in the traction current [10,21,22]. Moreover, it is assumed that the allowed margin factor characterizing the distance between the track circuit signal causing the track relay excitation and interference should be at least 20%, and for deexcitation 10% [17].

Electromagnetic interference from electric transport systems and rolling stock requires precise assessment methods. The applicable standards are often considered insufficient due to the complexity of the interference sources and the lack of sufficient research [11]. This paper presents a comprehensive and up-to-date approach to the complex problem of electromagnetic compatibility (EMC) testing in railway applications, with particular attention to current regulatory requirements and the specific challenges of real-world testing scenarios. A key contribution of this work is the detailed presentation of the measurement methodology and test procedures for the electromagnetic compatibility of rolling stock with train detection systems using track circuits. The proposed methodology is fully aligned with the most recent legal and normative frameworks, including ERA/ERTMS/033281 version 5.0, Annex S-02 of the List of the President of the Railway Transport Authority and the technical specification CLC/TS 50238-2. This paper also includes a critical analysis of the major changes introduced in the latest editions of the applicable standards. These changes concern not only the tested frequency bands and permissible interference current levels but, more importantly, the way in which parameter changes are evaluated. This paper highlights important differences, such as the increase in the minimum overlap time of measurement windows and the introduction of additional assessment criteria (permissible exceedance duration, minimum time between consecutive exceedances), as a result of frequent updates to the relevant documents. Additionally, this paper presents measurement results and analyses obtained from tests conducted under actual operating conditions on a prototype vehicle. Real-world testing poses additional challenges due to uncontrolled sources of electromagnetic interference, which require strict compliance with applicable standards and a rigorous implementation of measurement procedures.

2. Materials and Methods

Attempts to systematize issues related to compatibility between rolling stock and train detection devices have been sanctioned in the CLC/TS 50238-2 specification [23], which generally describes the methodology for its determination, as well as in subsequent editions of the documents of the European Railway Agency ERA/ERTMS/033281 [24,25] and in the Letter of the President of the Office of Rail Transport [26], changing the method of measurement and the criteria for assessing the results. A common practice during tests is to supplement them with the determination of psophometric currents based on the relationship given in the PN-EN 50121-3-1:2017-05 standard [27] and the transient current results from the provisions of the PN-EN 50388-1 standard [28], which allows one to obtain a comprehensive picture of disturbances in the considered scope. The psophometric current is an equivalent disturbance current that represents the effective disturbance of a current spectrum in a power circuit to a communication line. The list of regulatory standards is summarized in

Table 1. The list of regulatory standards.

No.	Standardization Document	Standardized Testing Procedures
1	CLC/TS 50238-2:2020	Methodology for measuring the interference current
2	PN-EN 50121-3-1:2017-05	Psophometric current requirements and measurements
3	PN-EN 50388-1:2023-05	Transient current requirements and measurement
4	ERA/ERTMS/033281	Requirements for interference currents
5	List of the President of the Office of Rail Transport	Specific Polish requirements for interference currents
6	PN-EN 15595:2019-03	Method of determining the initial adhesion coefficient
7	ILAC-G8:09/2019	Method of determining the compliance of the result with the requirements
8	Commission Regulation (EU) No 1302/2014	Introduces the requirement to measure interference currents

.

In order to ensure the safety of railway traffic, vehicles must undergo a number of tests related to the examination of disturbances generated, among others, in the return current to the mains. The requirement to carry out the above tests results from the provisions of the List of the President of the Office of Rail Transport (UTK) [26], as well as from the requirements of Commission Regulation (EU) No. 1302/2014 on the technical specification of interoperability relating to the “Rolling stock—locomotives and passenger rolling stock” subsystem of the railway system in the European Union [29]. However, this problem is complicated by the inability to perform such measurements under laboratory conditions. Carrying out tests in real conditions determines the emergence of additional potential sources of interference, from the power source to the improper cooperation of the current collector with the overhead contact system, and it introduces the need for rigorous compliance with normative requirements and the application of test program standards.

The basic document that specifies the method and conditions for carrying out compatibility measurements between train and rolling stock detection systems is the CLC/TS 50238-2:2020 specification [23]. The tests should be carried out in accordance with the recommendations regarding infrastructure described in point 6.2.4.3 of Annex B of the specification [23]. Measurements of the variable and constant components of the traction current are carried out in the main circuit, in various operating conditions of electric multiple units (EMUs) and locomotives: at a standstill, when starting and stopping the vehicle, sudden changes in speed, starts and electrodynamic braking carried out in normal and low-traction conditions. Electrodynamic starting and braking tests are also performed with half the traction power and with one inverter turned off as a failure simulation. Additionally, measurements are recorded during starts to maximum speed and electrodynamic (ED) braking to stop for two cases: (a) at a short distance from the power supply substation and (b) at distance of >15 km from the substation. The tests performed are summarized in

Table 2. The list of tests performed.

No.	Type of Test		Speed [km/h]
1	Background		-
2	Starting the vehicle		-
3	Turning off the vehicle		-
4	Standby (near the substation)		-
5	Standby (far from substation)		-
6	Changing the speed manually		60 ⇒ Vmax Vmax ⇒ 60
7
8	Cruise control speed change		60 ⇒ Vmax Vmax ⇒ 60
9
10	100% traction power—measurement close to the substation	Start	0 ⇒ Vmax
11		Braking	Vmax ⇒ 0
12	100% traction power—measurement far from the substation	Start	0 ⇒ Vmax
13		Braking	Vmax ⇒ 0
14	50% of traction power—measurement close to the substation	Start	0 ⇒ Vmax
15		Braking	Vmax ⇒ 0
16	50% of traction power—measurement far from the substation	Start	0 ⇒ Vmax
17		Braking	Vmax ⇒ 0
18	Inverter turned off—measurement close to the substation (failure simulation)	Start	0 ⇒ Vmax
19		Braking	Vmax ⇒ 0
20	Inverter turned off—measurement far from the substation (failure simulation)	Start	0 ⇒ Vmax
21		Braking	Vmax ⇒ 0
22	100% traction power—limited traction (measurement close to the substation)	Start	0 ⇒ Vmax
23		Braking	Vmax ⇒ 0
24	100% traction power—limited traction (measurement far from the substation)	Start	0 ⇒ Vmax
25		Braking	Vmax ⇒ 0

. The test documentation should include the location of the test, e.g., by entering the starting kilometer of the appropriate railway route.

Furthermore, in the case of tests with reduced adhesion, according to the requirements of the CLC/TS 50238-2 specification, the initial adhesion coefficient must be in the range of 5 to 8% [19]. The initial adhesion coefficient for tests with reduced adhesion is calculated based on the standard PN-EN 15595:2019-03 [30] from the following relationship:

$$\tau ={\displaystyle \frac{\overline{a}}{g}},$$

(1)

where τ is an initial adhesion coefficient, ā denotes delay value in the first interval (Figure 1), and g is an acceleration due to gravity (constant value).

Measurements of the interference current I_z should be performed using two data-processing algorithms:

1

Algorithm using the fast Fourier transform (FFT);

2

Algorithm using band-pass filters (BPFs) in accordance with the documents [24,25].

The calculated values of the I_z current refer to the requirements of Annex S-02 of the List of the President of UTK [26], regarding permissible levels and parameters of disturbances for railway traffic control devices for locomotives and electric multiple units and point 3.2.2.6. of document ERA/ERTMS/033281 [24,25]. The limit values are included in

Table 3. Permissible interference currents from locomotives and electric multiple units—Annex S-02 to the List of the president of UTK [26].

Sensor Type	Frequency [Hz]	Current [A]	Sensor Type	Frequency [Hz]	Current [A]
Classic circuits track	2–40	15	SOT—1	2680–2730	0.095
	40–45	3.11		2740	0.044
	45–48	1.85		2750–2900	0.018
	48–52	1.20		2910–2950	0.044
	52–55	1.85		2960–3030	0.108
	55–60	3.11		3040–3090	0.231
SOT—1	1370–1400	0.396		3100–3120	0.396
	1410–1440	0.231	SOT—2	6650–6700	0.425
	1450	0.175		6710–7210	0.015
	1460–1480	0.094		7220–7600	0.100
	1490–1510	0.066		7610–8720	0.015
	1520–1670	0.027		8730–9590	0.425
	1680–1700	0.066		9600–10,500	0.022
	1710–1750	0.217		10,510–11,650	0.425
	1760–1780	0.117		11,660–12,700	0.034
	1790–1910	0.032		12,710–14,040	0.425
	1920–1930	0.095		14,050–15,290	0.037
	1940–1950	0.127		15,300–16,110	0.425
	1960–2060	0.207		16,120–17,590	0.021
	2070–2120	0.068		17,600–17,650	0.425
	2130–2270	0.018	EOC	24,300–25,100	0.425
	2280–2320	0.141		25,300–27,130	0.035
	2330–2370	0.076		27,140–27,690	0.425
	2380–2550	0.019		27,700–29,900	0.038
	2560–2570	0.050		30,000–30,300	0.425
	2580–2600	0.118		30,400–32,700	0.038
	2610–2670	0.189		32,800–33,000	0.425

and

Table 4. Permissible interference currents—ERA/ERTMS/033281 [24,25].

Frequency [Hz] [Hz]	Current [A] [A]	Algorithm
70.5–79.5	1.9	band-pass filters (BPFs)
205.5–245.4	4.0
270.5–279.5	1.9
1900–2700	2.2
2700–5100	1.5
3450–7550	1.5
4650–6360	1
9200–16,800	0.5
9320–16,755	0.33
1500–3200	0.3/3 1	FFT transform
9436–9564 2	0.3

¹—a change has been introduced in the permissible current value. ²—a change has been introduced in the frequency band.

, highlighting the changes that have been introduced with the new edition of the document. Analyzing the differences in the scope of the tested frequency bands and permissible values of currents, they are small, but in terms of the method of assessing the parameters of changes, there is much more; among other things, the minimum window overlap time has been increased. Additional assessment parameters have been introduced: the permissible duration of exceedance and minimum time between subsequent exceedances. In the scope of the application of Annex S02 to the List of the President of UTK [26], no differences were found between subsequent editions.

Figure 2 shows the permissible interference levels graphically, in red, resulting from Annex S02 to the List of the President of UTK [26] and in brown for the limit resulting from document [24] regarding the FFT and BPF processing algorithm. During the analysis of the results, the extended laboratory uncertainty is considered, which is marked as Ulab (Iz). The uncertainty value includes such factors as the uncertainties of individual elements of the measuring system resulting from the calibration certificates, the resolution of these devices and the resolution of the indications. Finally, the extended uncertainty, depending on the current range I_z, is 0.53 to 78.92 mA.

The installation of a measurement system, which may contain various types of measurement transducers, should be preceded by a thorough analysis of the vehicle’s drive system. Based on the diagram of the vehicle’s main power supply circuit, it is necessary to select the connection points for the transducers to measure current and voltage. In each case, the equipment of the measurement system and the method of running the measurement’s installation will depend on the specificity and construction of the vehicle being tested, and therefore it is not possible to describe it precisely.

A description of the measurement system, together with the specification of the measuring equipment used, is included in the test report. The measurement results are presented in graphical form for selected and marked samples. The charts are presented in the frequency band 2 Hz–33 kHz, which is a reference to the frequency ranges specified in Annex S-02 of the President’s Letter [26] and in the document ERA/ERTMS/033281 [24].

3. Results and Discussion

The measurement results presented in this paper were obtained from tests carried out on a prototype three-car electric multiple unit (EMU) supplied via a 3 kV DC overhead catenary system. The unit is designed for a maximum operating speed of 160 km/h and has a total installed traction power of 1.2 MW. The traction system comprises two traction inverters, each rated at 390 kW, as well as two auxiliary inverters, each with a nominal power output of 80 kW. The tests were carried out on a test track powered by a traction station, the characteristics of which are known and can be taken into account when analyzing the results. During the tests, there was no other receiver in the power supply section that could be a potential source of additional interference.

The measuring transducers and their measuring installations are installed in places where a high voltage is present. Therefore, it is absolutely necessary to ensure the safety of the measurement team against electrocution and to protect the equipment used in research against damage.

The general diagram of the measurement system for testing disturbances in the return current to the traction network is shown in Figure 3. The actual measurement system installed at the test facility is shown in Figure 4.

An example set of measuring equipment in relation to Figure 3 is presented below:

(a)

Measurement of the alternating component of the traction current Iz—Rogowski coil;

(b)

Measurement of traction current It—current–voltage transducer;

(c)

Measurement of the traction network voltage Ut—voltage transducer;

(d)

Measurement of vehicle speed and deceleration v, a—VBOX device;

(e)

Speed measurement v1–v4—axial sensor with 1–4 axes.

For recording the parameters listed in points a–e, it is necessary to use a digital recorder enabling real-time calculations and the acquisition of all parameters.

Figure 5, Figure 6, Figure 7 and Figure 8 show sample measurement results. The course of the fault current value is shown in green for FFT and light green for BPF. To determine compliance with the requirements, the principle of simple acceptance, described in point 4.2.1 of document ILAC-G8:09/2019 [31], was used.

Frequency bands for which conditional compliance criteria were applied with a probability of 50% are marked with blue rectangles described in the legend as “Iz + Ulab(Iz)”. Frequency bands for which the conditional non-compliance criteria were applied with a probability of 50% are marked with orange rectangles described in the legend as “Iz − Ulab(Iz)”. Exceeding the permissible levels are marked with pink squares described in the legend as “Iz − Ulab (Iz) > Limit Iz”.

Figure 5 presents the results of background measurements obtained when all power electronic devices on the vehicle are turned off, and only the system enabling the current collector to be lifted under the traction network is operational. Figure 6 shows the results obtained when starting the vehicle up to the maximum speed, and Figure 7 shows the results obtained during the braking test for the same object. It should be noted that during braking, we are dealing with recuperation, because only on test sections that can receive energy can such tests be performed; hence, the differences between the characteristics are visible—Figure 6 and Figure 7.

Figure 7 and Figure 8 show the measurement results for the same object during full braking from its maximum speed to stop. The visible difference in characteristics results from the distance from the traction substation supplying a given section. The closer to the power source, the higher the level of interference. Based on this, it can be concluded that there are disturbances introduced by the substation itself. For a complete picture, it is necessary to perform background measurements, complete an analysis of the harmonics of the substation and include these results in the final characterization of the test object.

Figure 9 shows the characteristics with numerous exceedances (pink in the graph) of the permissible values recorded during tests related to maintaining a constant speed and then changing it in the cruise control system. The disturbances generated are related to the operation of the automatic regulation system. During an identical test with manual control, where the operation of the regulation system is much slower, this type of interference does not occur.

It is also necessary to carry out some tests under conditions of limited adhesion. Figure 10 shows the recorded current and voltage values when the vehicle loses traction after starting. A functioning vehicle anti-lock braking system must also not have a negative impact on the vehicle’s power system.

Power supply from the direct current traction network of electric traction vehicles requires the use of rectifier units installed at traction substations. The substation system includes transformers with various connection systems and rectifier systems composed of uncontrolled diode bridges. Thanks to the multiphase nature of these transformers, rectifier systems can be obtained with an increased number of rectified voltage pulses per one supply voltage period. Simpler systems that are still used are six-pulse rectifier systems. These systems are based, for example, on a three-phase transformer with a Yd connection system and a bridge rectifier.

The number of pulses in the rectified voltage depends on the converter system used. However, the instantaneous and average value of the rectified voltage and harmonics, apart from the structure and number of diodes in the rectifier, are influenced by many other factors. These include, for example, the symmetry of the transformer’s structure, the symmetry of the system’s supply voltages and their deformation from the sinusoid and operation in the linear range of the transformer’s magnetization characteristics, as well as, in a system consisting of a transformer and a rectifier, the nature and quality of commutation processes [9].

Based on the technical parameters of the adopted solutions of the power supply transformer, choke, rectifier and input filters used on the vehicle, analytical calculations of the generated harmonics in the output voltage of an ideal substation are performed [32]. Example results of analytical calculations obtained up to the sixtieth harmonic are presented in

Table 5. Harmonic contribution to voltage for U = 3300 VDC.

Order of Harmonic n	Frequency [Hz]	Harmonic Voltage Value [V]	Share Value [%]
6	300	133.32	4.04
12	600	32.67	0.99
18	900	14.52	0.44
24	1200	8.25	0.25
30	1500	5.28	0.16
36	1800	3.63	0.11
42	2100	2.64	0.08
48	2400	1.98	0.06
54	2700	1.65	0.05
60	3000	1.32	0.04

. However, initial harmonics, i.e., 6th, 12th, and 18th order, etc., have the highest value but are relatively easy to identify, as they result from the specifics of the operation of typical rectifiers at the output of a substation, 6- or 12-half traction. A problem during analysis is caused by harmonics in the range of 24–36, where there are particularly low values of limits for interference currents. Higher harmonics in practice cease to be important because of their values.

An actual traction substation requires taking into account additional phenomena such as a variable commutation angle depending on the current drawn from the substation or asymmetries of the transformer and power supply system and distortion of the substation supply voltage. In such a case, analytical calculations must be replaced by simulation calculations based on an adopted model that takes into account these additional phenomena.

In order to determine the harmonics in the traction voltage and current of the substation, taking into account additional parameters that can affect the spectrum of harmonics in the traction current, simulation analyses were carried out for the model of a six-pulse traction substation. In the simulation model of the rectifier set, one working rectifier transformer with a Δ/Υ⅄ connection system + equalizing choke connected to a six-phase rectifier was assumed, as well as their parameters based on the provided data. Two versions of the substation were analyzed, without the smoothing device (filter) switched on and with it switched on. The load currents and output voltages of the substation were similar to the values during the measurement runs. The simulations assumed symmetry of the supply and a resistive load close to the substation. In order to illustrate the different operating conditions of the substation, calculations of harmonics in the output voltage and current of the substation were performed for selected configurations of substation filters and for selected load currents. The choice of the current value in the calculations was related to the measurements carried out for the substation loads of the tested vehicle. Example results of voltage harmonics are shown in Figure 11, while current harmonics for different configurations are shown in Figure 12 and Figure 13.

An analysis of the measured harmonics in the current shows typical dominant harmonic values for the band from 50 Hz to 1000 Hz. Since the substation is the power supply during the EZT tests, the levels of generated harmonics in the current should be related to the requirements for the limit values of these harmonics for traction vehicles.

As mentioned in the introduction, complementary tests include the psophometric current (equivalent to the interference current in the required frequency band) generated to the overhead contact system. The measurement of such a current is carried out in the same system as the previous measurements (Figure 2)—in the main circuit using an algorithm using FFT.

The value of the psophometric current I_pso is determined based on the relationship given in the PN-EN 50121-3-1:2017 standard [27].

$${\mathrm{I}}_{\mathrm{p}\mathrm{s}\mathrm{o}}={\displaystyle \frac{1}{{\mathrm{p}}_{800}}}\sqrt{\sum {\left({\mathrm{p}}_{\mathrm{f}}{\mathrm{I}}_{\mathrm{f}}\right)}^2}$$

(2)

where I_f is an alternating current component with frequency f in the traction current, p_f is a psophometric weight factor [33], and p₈₀₀ denotes the p_f value for a frequency of 800 Hz (p₈₀₀ = 1000).

The requirements for transient current measurements result from the provisions of the PN-EN 50388-1 [28] standard, point 11.5. The purpose of this type of measurement is to ensure that there are no undesirable actions by the safety devices in the traction substation. The transient current must be recorded during the vehicle starting procedure when the quick-release switch is activated. The limit values are shown in

Table 6. Limit values of transient current in time periods.

T [ms]	Required di/dt [A/ms]
<20	di/dt < 60
>20	di/dt < 20

.

A comprehensive analysis should include analytical calculations, simulation calculations and an assessment of the measurement results of the traction substation. Example elements of the analysis were performed in terms of generating disturbances, in particular, harmonics in the substation output current. This issue is particularly important when testing traction vehicles powered by this type of system in order to isolate interference generated by the substation itself. Only a comparison of the obtained results will show whether the levels of harmonics in the substation output current for the analyzed cases of vehicle cooperation with substations do not exceed the permissible values according to [23,24] for this parameter.

4. Conclusions

This paper presents issues related to the research and analysis of electromagnetic compatibility with train detection systems based on track circuits, a topic that is quite complicated and difficult to implement in practice. The complexity of the tests, including the number of tests to be carried out under various conditions and the need to perform them multiple times to ensure the repeatability of the results, as well as the need to take into account so many factors affecting the results, requires a very careful approach to their performance and, even more so, the analysis of the results obtained. The determination of harmonic components in the traction current in relation to the permissible levels specified in the latest and frequently updated editions of documents requires their constant supervision. The subject of this type of measurement was discussed in detail, and, referring to the normative requirements, the procedures for conducting research were defined. However, from the authors’ experience, further work seems necessary to improve the ability to identify external sources of interference affecting the obtained results.

Research on the electromagnetic compatibility of rolling stock, while focused on interaction with track circuits, is part of the broader context of ensuring the stable and trouble-free operation of evolving railroad microgrid systems. Understanding and minimizing electromagnetic interference is essential for the effective planning and control and reliable operation of these advanced systems.