Abstract: The invention provides a tunnelling shield including a plurality of axially extending rams fixed therein for thrusting against a tunnel lining erected behind or within the rear portion of the shield, a fluid pump, a motor for driving the pump and a fluid reservoir for supplying fluid under pressure to the rams, the improvement wherein the fluid pump and the motor are mounted on the inner periphery of the shield at the bottom of the shield and at least one fluid reservoir is mounted on the inner periphery of the shield at a location spaced from the fluid pump and the motor.