Method for measuring and correcting straightness of railroad of carriage

PURPOSE: A method for measuring and correcting the straightness of a railroad for a towing carriage is provided to easily and accurately correct the straightness of the railroad for the towing carriage of a vessel by installing simple equipment, thereby reducing the transverse vibration of the towing carriage in a model test. CONSTITUTION: A method for measuring and correcting the straightness of a railroad (1) for a towing carriage includes the following steps of: arranging a piano wire (2) parallel to the railroad; attaching a height gauge (4) having a predetermined height erectly onto the railroad with a magnetic (3) on the tip end portion of the towing carriage; and focusing a microscope (5) joined to the height gauge on the piano wire while the microscope is vertically moved by the operation of the height gauge.