RTG's as mentioned. Last ones I saw were at Chambery in the French Alps, perhaps the photgraph was taken in that region? I used them a lot travelling from London to Paris before Eurostar, when the Boulogne (Aerogliseurs) - Paris service were RTG's.
David Kingston 17:07, 06-07-2011
See on Wikipedia :
Could the sender please let me know who they are. John