The 400 Series is a 2 wheel drive configuration powered by petrol or gas. It can carry up to a maximum of 30 passengers via three 100A Series Carriages.
Specific details on each are available via the following links:
Specifications - 300/400/500/600 Series Prime Mover (Petrol/Gas)
Specifications - 100A Series Carriage
Here is a selection of pictures detailing various aspects of this trackless train. All pictures here are for various prime movers each with 8 seater carriages, but this model prime mover can also tow the standard 100A carriage, pictured below.
Click to enlarge