by Allen Hazen
Boxpok -- a proprietary name for the General Steel Castings design -- were the most commonly used disc driving wheels on late American steam locomotives, but the Baldwin Locomotive Works had its own type: recognizable from the raised "lips" around the openings and, if you get a good view, from the words "Baldwin Disc Driver" cast on the face of the driver center. I think they were broadly comparable in physical characteristics. Baldwin drivers were used in a number of locomotives of the late 1930s -- Santa Fe Hudsons and Northerns, for example -- but a reasonable number of late Baldwins, notably the (production) T1 duplexes for the Pennsylvania -- had Boxpok. Is there some (known and interesting) reason why they used Boxpok instead of their own version on these late locomotives? (The obvious thought is that there was a cost advantage. But -- given the collapse in the market for steam locomotives in the 1940s -- I would have thought that Baldwin would have had plenty of capacity at their own foundry, so I would be surprised if they were unable to produce in-house driving wheels as cheaply as they could buy them from a subcontractor.)