Real world
This wagon is used rarely nowadays. It is very versatile, so it can carry almost any cargo (arbitrarily shaped pieces of wood, metal plates, concrete panels, castings and much more) and is often used to transport military vehicles of any kind.
Model
Just add buffers (order here or here) and two Y25 type chassis and paint it and you are ready to go! Two hexagon bores at the bottom enable you to add two M3 nuts (1.4mm height), so you can screw chassis to the frame and easily dismantle them later on. Use 7.7mm diameter wheels only. Optionally, you can add nine stanchions on both sides and two stanchions on both ends of the wagon. There are holes and bores ready for this.
Technical specifications
You can order Y25 type chassis here.
You can order buffers here or here.
You can order optional accessories here.