The Thumpers built for Northern Ireland the 80 and 450 Class were built in England at Derby and shipped over.
We found some images in a book about BREL which is what the BR works were known as in the 80's by Colin J Marsden showing some vehicles under construction.
The shot above shows a trailer vehicle for an 80 Class under construction
Another shot we had was one posted by Martin Baumann in our Facebook Group which came from his vast collection
This is of 95 at Derby on 31-03-78
Above is a 450 Power Car under construction, this may be 454 as there is a 4 marked on the body with chalk in a few places.
An error in the book refers to these as a 451 Class not 450
A shot we found on line of two 80 Class trailers at Derby
These are temporally fitted with BR Gauge bogies to enable movement around the works
This was taken on the 10th September 1977 and the vehicles are possibly 740 & 741
Image by Derek Patterson
Another two vehicles the one centre looks like a centre car and the one on the right is a driving trailer
Northern Ireland Railways
Thumpers Under Construction