Electromagnetic Compatibility

RSA specializes in Electromagnetic Compatibility work. We have worked in both United States based U.M.T.A./FTA standards and E.N. standards for signaling and rolling stock applications. 


Conducted Emissions



Track Circuit Compatibility- UMTA
Conducted Emissions testing involves measuring and analyzing the conducted current noise emissions resulting from electrified railways rectifiers and various switching power electronics. On systems where AC track circuits are utilized, it is important to mitigate emissions such that they do not interfere with the frequencies utilized for train detection.



Psophometric - EN 50121-3-1
Noise contained within the supply current to the electrified rolling stock can interfere with wayside cabling, in particular, that used for telephony communications. Utilizing specialized filtering design to examine the audible frequency range, rolling stock and rectifier are tested to ensure normal telephony operation.


Inductive Emissions




Track Circuit Compatibility - UMTA
When rolling stock passes over an AC track circuit's impedance bond, it creates a loop between its axles and the impedance bond itself. Magnetic field emanating from the undercarriage area of the vehicle cause a circulating current to be induced in this formed loop, potentially falsely energizing a track circuit. Testing for this phenomena consists of measuring the induced noise in the impedance bond/axle counter loop, and ensuring it does not pose a hazard to proper train detection.



Axle Counter Compatibility - EN 50238
Axle counting devices utilize a loop based antenna in their receiver to interpret the influence of metallic rolling stock structure on their created field. The magnetic field generated by passing rolling stock can sometimes interfere with this train detection, erroneously causing additional axles to be counted or not counting them at all. In order to test for this magnetic field, a specialized antenna is attached to the rail to mimic an axle counter, and measures the field induced to ensure that it does not interfere with the axle counter's proper operation.



Radiated Emissions




UMTA - EN 50121-3-1
Often times high power electrical equipment, such as that found on electrified rolling stock, can cause emissions that interfere with proper radio device operation. Radiated emissions testing tests the ambient conditions of the installed environment and compare that to the measured radio frequency signature of the electrified rolling stock in operation. A thorough analysis of this emissions signature ensures that no radio users in proximity to the electrified rolling stock are adversely affected.  



Human Exposure to Non Ionizing Radiation (Magnetic Fields)




ICNIRP - EN 45502
Electrified rolling stock and traction power installation create powerful magnetic fields, resulting from the large currents passing through their conductors. When exposed to excessive levels of magnetic fields, humans can be at risk of adverse health effects. Careful design consideration is necessary to mitigate such effects. In order to ensure safe levels of magnetic fields are maintained in spaces designed for human occupancy, an array of testing is completed to measure and ensure magnetic fields remain at compliant levels.