Abstract: A vehicle for travel through a conduit includes a forward and a rearward member, each member being provided with a wall-engaging mechanism for selectively engaging a wall of the conduit to hold the respective member in a stationary position within the conduit. Extensible elements such as a hydraulic ram connect the members for relative movement of the forward member toward and away from the rearward member. Each wall-engaging mechanism includes a plurality of legs extendable outwardly from the respective member and a wall-engaging surface on or fixed to each leg, one actuator engages each of the legs for coordinated extension of the legs to bring each wall-engaging surface into contact with the wall of the conduit. Preferably a rotary cuter is mounted at the front of the vehicle for clearing obstructions in the conduit.