An hydraulic control arrangement (66) in association with a pipe relining machine Includes fluid pressure supply and return lines (32, 33), a motor controller (80) to control a motor (67) and a radial position controller. The radial position controller supplies fluid under pressure to a radial positioning arrangement (46) to set diameter of a relined pipe. The radial position controller has a first normally closed valve (83) supplying fluid under pressure to the radial positioning arrangement (46) and a second normally open valve (84) allowing fluid to be withdrawn from the radial positioning arrangement (46). The arrangement (66) allows the pipe relining machine to be withdrawn in the event of a failure.