Paxman Valenta 12RP200L with an integral Brush alternator. The Valentas in
the XPT were downrated from 1680kW to 1475kW with 1350kW available for
traction. The trailing power car supplies auxiliary train power and only
has 1150kW available for traction.
I have a photo of a brand new Valenta I took at the ABB factory in 1992.
The unit ended up in XP2016. I'll see if I can find time to get it scanned.
Cheers
David