The H30 was a covered hopper, primarily intended to be used for transporting cement. The covers protected the material from the weather, while the three bays allowed for quick unloading. The car measured 37 feet end-sill to end-sill. They were capable of carrying 70 tons. Because of their frame design, their sides look like a bridge truss. There were 1,325 of these cars built between 1935 and 1949. The photo shown here was taken by me of PRR #255750 at the Railroad Museum of Pennsylvania in Strasburg, PA on August 11, 2013. The only real difference between an H30 and an H30a is the bolsters. The H30's bolsters were cast, while the H30a's bolsters were welded. The ones on PRR #255750 are welded, so that is technically an H30a. By the way, the Norfolk & Western had 60 "HC-1" cars which were virtually identical to the PRR H30.