Villeneuve Saint George shop, both diesel locomotives are used to move high speed trains in the shop. Yellow high speed postal train was the half trainset (1 engine and 4 coaches) for spare in case of collision or big issue of a plain postal trainset.
All others high speed postal trains are retired from end of June 2015, and now scrapped, The French postal company don't want to pay the expensive cost of the half life needed renovation session !
Behind postal half train, there is 2 coupled TGV engines which are spare engine, first is a multi-power serie and is compatible with all TGV trainsets except first serie (TGV SE) where the second one is for.