Abstract: A dolly for connecting two trailers in tandem comprises an axle, wheels rotatably mounted thereon, a fifth wheel secured to the axle, two towing eye hooks spaced apart from each other for connecting the dolly to the rear of the lead trailer so that controlled backing up of the entire tractor trailer rig is facilitated, and a sleeve swivelable about a tongue in such a manner so that the dolly may be hooked to the rear of the lead trailer on uneven ground and further so that side drag or "scooting" of the rear wheels on the lead trailer is avoided.