A mobile frame has a mounting platform underlying the mobile frame which is mounted for swinging movements toward and away from the upper surface of a strip of concrete pavement at a constant degree of angular relationship with the pavement. A plurality of cutting discs are mounted in tandem on the platform for rotation in a common vertical frame. Hydraulic power devices driven by an engine and control apparatus are provided to drive the cutting discs, impart movements to the platform, and impart steering and driving movements to the wheels of the mobile frame. A flow of liquid coolant is provided for the cutting discs and the cutting discs are so disposed relative to the mobile frame that each disc rearwardly of the front disc cuts into the pavement at a greater depth from the surface of the pavement than the preceding disc. A trolley device connected to the steerable wheels of the mobile frame guides the mobile frame in its path of travel along the pavement.

The ditcher is provided with two engines. The first engine powers the hydraulic system which rotates the digging wheel. The second engine powers the hydraulic system which actuates the wheel lifting cylinders, the conveyor system and the track driving means. The two hydraulic systems are selectively interconnected so that, in the event that the second engine fails, the first engine can be used to actuate the wheel lifting cylinders and track driving means. As a result, the ditcher's wheel can be lifted to the travelling position and the tracks driven to move the ditcher off the pipe line right-of-way and enable it to return to a base camp for repairs.