I dont have any French Bugatti/Streamliners ( yet ...lol) so hopefully @FRENCHTRAINS Daniel will pop in ... its probably relevant here that French Hornby was a company in its own right so its pure guesstimation as to what if any UK hornby components are compatible although by eye the motors look the same format in such things I do have like the MO ... and certainly Hachette although of the right size and configuration has literally nothing to do with actual Hornby except in name ..
@Jim O'C Has some examples too If memory is correct?
Your PLM Railcar seems to be the lead car from this set
https://auctions.specialauctio...e%3D19%26view%3Dgrid
As to modern electrification you could try this chap here ...