Varying in power output and size, they are agricultural tractors on top of a four-wheeled steel rail wagon frame.

The shunters are not fitted with air brakes but are through-piped to enable them to be worked dead as part of a normal train.

[3] An exception to that is RT46, a standard "Aresco Trak Chief", the only one of its type built for the VR, which entered service in 1966.

[4] Units currently authorised to operate on Victorian tracks are RT 3-40, 42-43 and 45–53, the second group being more powerful, and all are permitted to travel at 15 km/h maximum.

[3] Units RT 18, 28 and 43 were gauge converted and transferred to Sydney for use on the construction of the Epping to Chatswood railway.