Firstly, while the Lima XPT power car is about the right height and width, it is longer than a scale model since it is a 1/76 model of the British HST power car which is longer than the XPT power car in real life.
The real XPT has a wheel spacing very similar to the USA General Motors cab locomotives types F3 to F9.
These are readily available in HO but the chassis would be too short for the Lima body.
The hood units types GP38, GP40 to GP60 are longer but have the same bogies.
These might be suitable, and there are hundreds of such models available from many manufacturers.
The bogie sideframes are not correct for an XPT and these would have to be scratchbuilt using the Lima trailer bogies as a guide to the appearance.