Matchbox King Size No. 8 Scammell with Trailer: Early version with metal hubs!

6x6 Tractor is also called a Prime Mover, has a spare tire & wheel on the back
Trailer has 12 wheels (each wheel position has dual wheels)
All 19 wheels have metal hubs!

Overall this rig measures 12 inches long

From my personal collection: Smoke-free home, one owner.