I reckon the definitive answer is probably to be found in the following publication:
"Allied military locomotives of the second world war", by R. Tourret. - Tourret publishing (ISBN 0-905878-06-X).
I don't write this to give you a hard time or upset you, but I would have thought it was blindingly obvious that TVR 610 was built to the same basic design and specification as the wartime S-160s. I can see this just by looking at the photos you've posted - any differences between the two are merely cosmetic.
If you want a model of this engine, the obvious way to get one is to modify the available kit for the S-160.
Cheers,
Mark.