Oui..
When I seen this thread "de-de, di-de" immediately came to mind! It's just le best!!

Look on YouTube and you will find so many versions and remixes of it. I have most of them on my phone.
Besides le SNCF jingle my other favourite has to be the old chime at Roissy Aéroport that was used for many years "Indicatif Roissy" composed by Bernard Parmegiani for Aéroports de Paris in the 70's. Now replace by "Indicatif ADP"
As mentioned above the SBB-CFF-FFS is also awesome.
I also quite like the short and simple bing bong at München Hauptbahnhof, the MVG chime is also cool.
And who could forget the old classic bing-bong chime at Glasgow Central that was there for more than twenty years?! I grew up hearing that and will be stuck in my mind forever!