Designed in 1960 by the N&W as the H-11 class which is an enlarged PRR H-39 70 ton hopper. In 1964 the size was increased to 12' 3" high cubic feet increased to 3433 and weight capacity increased to 90-100 tons. Over 130000 have been built. Three distinctive characteristics highlight this class of hopper roping eye with integral end buffers end slope sheets are at a steeper angle than the hopper sheets 13 riveted side posts with the middle two panels wider than the rest. Other features include Wine door locks and full height side ladder stiles. Pullman Greenville Steel Car and Trinity built similar cars. The cars were built by PRR B&O C&O N&W and RDG. Bethlehem Steel and ACF supplied prefabricated kits to other railroads. The following used these hoppers B&O Blue Diamond Mining BN C&I C&O CONRAIL CHESSIE SYSTEM (B&O) CHESSIE SYSTEM (C&O) CHESSIE SYSTEM (WM) CHESSIE SYSTEM (CSXT) CHESSIE SYSTEM (CSX) Dayton Power & Light D&H D&RGW Island Creek Coal Intsel Corp ITEL LEF & C L&N LRWN MKT Missouri Public Service MSDR NORFOLK SOUTHERN N&W NP NS P&LE P&S Potomic Electric Power Co PENN CENTRAL Penna Power & Light PRR PVAL READING ROCK ISLAND SANTA FE SEABOARD SLSF (FRISCO) SOO SOUTHERN PACIFIC TWRY UMP UMPX UNION PACIFIC UPPER MARION AND PLYMOUTH and WESTERN MARYLAND. Ready To Run Roller Bearing Trucks with metal 36" wheels interior & slope sheet braces and knuckle couplers.