The present invention relates to a frame replacement system for replacing the frame of the rolling mill of a rolling assembly. The frame replacement system comprises a rail system. A replacement vehicle is capable of moving along the rail system. The rail system comprises a first line and a second line. The first line and the second line extending in different directions to be mutually connected with a railroad switch. The first line is parallel to the rolling axis of the rolling assembly. When the replacement vehicle is positioned on the first line and/or the railroad switch, the frame of the rolling mill is moving from the rolling assembly to the replacement vehicle or is moving from the replacement vehicle to the rolling assembly.