Here are three models of miniature lorries built using mostly the 28mm tyres found in the Meccano system.
They all share the same traction unit, shown in the first photo, which has six wheels — there is no steering or motor due to the size. Construction is evident from the photo.
The later photos show simple trailers attached to the traction unit to make small articulated rigs. One is a machinery type, one is a container flat trailer, and the other is an open trailer. They all use the 28mm wheels, except the machinery one that uses tyres for ½” pulleys.