To provide a dimension measuring method for a bogie frame for railroad as a large-sized structural member to measure a molded work for each bogie frame, whereupon the acceptability is judged through comparison with a design model on a personal computer and the marking-off for the mounting reference point to a machine for mechanical processing is conducted.

The attached illustration shows a measuring model S1 obtained by plotting on the personal computer the result from measuring the bogie frame three-dimensionally and the design model M1 of the bogie frame for the railroad. A conversion into a fit model is made by executing the processing to approach the measuring model S1 to the design model M1, and a comparison of the shape accuracy is made in such a way as laying it on the design model, and thereupon a judgement of the acceptability is passed. Marking-off for the mounting reference point to the machine for mechanical processing is conducted for each molded work judged as acceptable.