BS EN 50121-4:2016+A1:2019

What is BS EN 50121‑4 - Signalling and telecommunications of railway apparatus about? 

BS EN 50121 is a series of the European standard on railway applications that discusses electromagnetic compatibility so as to ensure an adequate level of emissions and immunity for rolling stock apparatus. 

BS EN 50121‑4 is the fourth part of the BS EN 50121 series of documents that applies to signal and telecommunication apparatus that is installed inside the railway environment. 

BS EN 50121‑4 specifies limits for emission and immunity and provides performance criteria for signalling and telecommunications (S&T) apparatus which may interfere with other apparatus inside the railway environment. 

The requirements specified in BS EN 50121‑4 applies for vital equipment such as interlocking or command and control, apparatus inside the 3 m zone, ports of apparatus inside the 10 m zone with connection inside the 3 m zone, ports of apparatus inside the 10 m zone with cable length > 30 m. 

Note: BS EN 50121‑4 does not specify basic personal safety requirements for apparatus such as protection against electric shock, unsafe operation, insulation coordination and related dielectric tests, but the test levels are sufficient to achieve satisfactory EMC in the majority of cases. 

Who is BS EN 50121‑4 - Signalling and telecommunications of railway apparatus for? 

BS EN 50121‑4 on railway application is applicable to: 

• Railway engineer 
• Manufacturers of the cables and telecommunications equipment 
• Mechanical engineer 
• Designers and users of electrical equipment 

Why should you use BS EN 50121‑4 - Signalling and telecommunications of railway apparatus? 

Electromagnetic compatibility (EMC) between electrical and electronic systems is an essential requirement for the reliable and safe operation of the train. 

BS EN 50121‑4 navigates you through the test method that constitutes the electromagnetic immunity requirements to ensure that the apparatus installed on railway locations have a sufficient level of immunity.  

BS EN 50121-4 establishes performance criteria for signalling and telecommunications (S&T) apparatus that may interfere with other apparatus inside the railway environment which specifies emission and immunity limitations as well as performance parameters. 

Overall, BS EN 50121-4 guides you through the EMC in railways that ensures the generic performance of signalling, traction, telecommunications and radiocommunications systems. 

In this way, the railway industry endeavours to reduce the risk of incidents and accidents occurring through electromagnetic emission and immunity characteristics of that equipment through identification processes and risk mitigation. 

What’s changed since the last update?  

BS EN 50121‑4:2016+A1:2019 supersedes BS EN 50121-4:2015. BS EN 50121‑4:2016+A1:2019 includes some technical changes with respect to BS EN 50121-4:2015. These include: 

• Revision of Annex ZZ.