The plant comprises a frame 1 which is moved via tracks 4 and 5 and has in the head part 2 hydraulic cylinders 19 for moving the plant. The hydraulic cylinders 19 carry a gripper 20 for interacting with the lining 21 of the tunnel. The plant also comprises a rock-extracting machine 7, a portal placer 8 for placing the tunnel lining 21 and a mortar-injection unit 10 arranged behind the placer 8 and having a base plate 11 which is connected to the movable frame 1 of the plant. The mortar-injection unit 10 is connected to the base plate 11 by means of travelling wheels 12 and by tracks 13 which are mounted on the base plate 11. The mortar-injection unit 10 is connected to the placer 8 by means of a drawbar 15 which ensures a rigid coupling between the placer 8 and the mortar-injection unit 10, the base plate 11 of the latter being connected to the end part 3 of the movable frame 1 by means of additional hydraulic cylinders 16. The present invention can be used particularly effectively in the construction of underground railway tunnels which are driven in hard, stable rock. <IMAGE>
