In 1898, Pressed Steel Car Co. built the first all-steel hopper car designated the GL. The Pennsylvania Railroad would purchase several thousand of this design. Due to production backlogs at P.S.C.Co. and flaws in the initial design, the Penny came up with its own all-steel, bottom-discharge hopper car in 1904 designated the GLa. Approximately 30,000 GLa’s were produced between 1904 and 1920. The Pennsy also built GLa’s for numerous coal companies who were anxious for the well-built and reasonably priced cars. Until the 1960’s, this design was one of the three most numerous classes of PRR freight cars. Although by this time, these cars began to rapidly disappear from the PRR roster, a few made it into the Penn Central and even Conrail rosters, lasting into the early 1980’s.