Very creative and wonderful models!
I ended this summer with 2 plus I "prototyped" a 50's truck conversion. In this pic the truck is in front, followed by a NENG railtruck, and a Bachmann off-the-shelf truck.
View attachment 60474
The NENG truck is very pretty. The kits were made 10-20 years ago, and the gent who put this together did a really nice job. NENG wheels and pickups were useless, so I added proper wheels and wipers.
Incidentally, The NENG truck uses a small motor and a NWSL drive gearbox. Pretty simple stuff. You can get similar motors from inside an HO loco, or as spares from Aliexpress.com in China.
If anyone is looking for really small spoked wheels (like the ones on the this truck and the blue one above,) they came from Slaters Plastikard in the UK. Stainless tires on a nylon moulded wheel, and 45mm shouldered axles (if you ask - otherwise 32mm.)
Here's the Slaters catalog page with the small wheels. 1ft diameter at 1:19th scale is 12/19ths inch, or about 5/8ths inch.