While standing on the platform waiting for the RER B train to Charles de Gaulle airport in Paris, I noticed codes like ELOT or EPEX besides arrival time, platform number, destination, etc.
What do these codes mean?
I didn't see any information in the station. RER B has two types of trains, one that stops at every station on the way and an express one that stops at a few stations (Gare du Nord, etc) before Charles de Gaulle airport. Can express trains be distinguished from these codes?
Note: the codes above are given as examples. Not sure they are accurate as I do this out of memory a few days after traveling in Paris. The second one I saw ended in EX but was not an express train.