Around Paris, Transilien (suburban train) stations all seem to have a few short rail segments between two rails, immediately preceded or followed by an even shorter raised thing. Here's how it looks like:


Here's a satellite view of another railway station with the short rail and the raised thing being clearly visible:


It doesn't seem to be guard rails: they are directly in the middle, there is a raised thing before/after short rail, and many of them are in the locations where the trains have little risk of derailment.

What is the purpose of this?

  • Is it along the entire length of track? Or could it be additional support by a breather switch? Commented Apr 28, 2019 at 12:29
  • I'm flagging this question as off-topic as it is not related to Travel. It seems to a be better fit for EngineeringSE. They have a tag dedicated for similar questions.
    – RedBaron
    Commented Apr 30, 2019 at 11:33
  • 2
    I'm voting to close this question as off-topic because it is not about travelling. Commented Apr 30, 2019 at 14:02

2 Answers 2


The long rail is actually an antenna. It is used for the EAS system. EAS is the french short for Equipement à Agent Seul, which means "sole-agent equipment". The antenna is used to transmit the video feeds of the platorm's cameras to screens inside the driving cab. The driver is able to remotely close or open the doors while watching for any incident, without the need for another agent. These antennas are used for Paris suburban trains (RER and Transilien), maybe for other trains as well.

Here is a picture with the onboard screens on the left :

Driving cab interior with EAS screens on the left

The short one is called a "Crocodile", as said in the other answer. The wikipedia page explains it better than me : https://en.wikipedia.org/wiki/Crocodile_(train_protection_system)


The short one is a so-called crocodile, a piece of safety equipment that transmits signals to the driver.

I'm not sure about the long one.

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