This model is intended for use with the Micro-Trains 40' drop bottom gondola. As such it is a good match for the Southern Pacific G-50-18 gondola with the 12'7" extension. These cars existed between 1965 and 1975. There were over 70 of this type made. Note that ladders need to be added. Contact me if you would like a copy of the arrow and car number decals.