Sorry to bring 00 gauge subjects onto the forum but one of our club members has a couple of cherished Trix Express 3 rail locos he'd like to bring back to life.
He asks whether replacement motors can be obtained for them or whether even replacement locos could be found. He sent me these pics and he's most definitely not computer savvy

First up is 2-6-0 item number 753




The other is an 0-6-0 item number 750

Replacement motors because they've failed, or because he wants to upgrade (probably not possible without a helluva lot of work)?

I would think best looking for scrap locos of the same model on ebay etc.  If the motor coil has failed it might be possible to get them re-wound.  A quick google search finds images of various old motors.

There must be a Trix forum/group out there that would be better placed to advise.

https://www.ttrca.co.uk/

My first venture into 'train sets' was a Trix Twin collection of two 0-4-0 tank locos some track and a few coaches. I was for ever cleaning the track and the pickups to try and get some reasonable running.
Probably a fairly basic motor and likely to need cleaning and new brushes before thinking of replacement motors if i remember the past.

If these are Trix Twin I am pretty sure they employ AC motors and control rather than DC, so if running with original track and equipment a suitable AC replacement would be needed - likely a donor loco will be the best option.