A tractor unit is a characteristically heavy-duty towing engine that provides motive power for hauling a towed or trailered load. The largest such vehicles are similar to locomotives. These fall into
Peterbilt 386 sleeper-cab–style commercial 6×4 tractor unit
A Leyland T45 cab-over 4×2 tractor unit
An Oshkosh M1070 8×8 Heavy Equipment Transporter (HET) tractor pulling a 5-bogie M1000 HETS trailer, carrying a slat-armored M93 Fox 6×6 NBC detection vehicle near Baghdad
Cab-over, also known as cab over engine, cab forward or flat face, flat nose, or forward control, is a body style of truck, bus, or van that has a vertical front, "flat face" or a semi-hood, with the
Volvo FH cab-over
The cab-over configuration is common for garbage trucks, as the short wheelbase allows a tight turning radius and the low cab height eases driver entry and exit.
Daimler Motor Lastwagen "Order No. 81", originally delivered to London in 1896, considered the world's oldest truck. Now in the Mercedes-Benz Museum