Thanks,
Yes Uvs, Both of them are based on Lima train bodies. One steam , one diesel. Lovely , detailed models.
Yes you should WM, the top bodies are the most difficult to build so it makes sense to find suitable train parts.
I still have loads from my childhood ( some still new ) and the tracks are perfect for this scale, so it's another plus. You can find sets for 28mm also.
The bottom parts are simple wood, card, pvc , bottle cap wheels , hard disk flat cable tracks , wire etc.
It is possible to build bigger ones, like a land train , also.
If you need help , ask.
Z