Grinding machine

A grinding machine comprises:-a first frame (2) mounted on four bull wheels (4) movable along a track (6) to be ground; a second frame (8) equipped with truckles (10) for supporting and moving along the track (6); -means for vertically moving the second frame (8) relative to the first frame (2); a third frame (14); the frame is located on a second frame (8) and is provided with at least three motor assemblies (28 and 28 ') with parallel axes, each shaft of the motor assemblies (28 and 28') is connected with a belt pulley (32) in an integral rotating mode, and the belt pulley (32) is connected with a grinding wheel (34) shaft in an integral mode; -means for vertically moving the frame (14) relative to the frame (8). The grinding machine is characterized in that at least one motor of the three motor assemblies (26, 28) and the grinding wheels (34) rotationally connected with the motor assemblies (26, 28) can generate translation through a device for determining the change of the center distance between the thre