The Yo 3500 is a JASCO car, and 1,345 cars were manufactured with new products and remodeling from 1950 to 1957. The support part of the leaf spring that receives and supports the axle is a single-stage type, and it is unsuitable for high-speed traveling. With the speeding up of freight trains a two-stage link type supporting 85kph traveling was produced from 1967, with most Yo 3500 have been remodeled to Yo 5000.