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?