I have been upgrading my storage for my vehicle collection. The corduroy cloth I am lining my plastic boxes is clear to see here in this box of M-60 series tanks and service & support vehicles.
Tractor trailers filled with supplies. These are resin palletized supplies. They fit in the back of these trailers, 2 1/2 ton trucks and even 5 ton Roco trucks.
In combat, units often fill up their vehicles with other gear. Here an M-577 based on one from a photo, shows a seat planted on top. Troops like to sit outside the vehicles in the 'Nam and sometimes put seat outside the vehicles, as shown here.