In source material, I have always seen XLT car hardware discussed in a B&O freight car context. QUESTION: has anybody seen XLT hardware mentioned in non-B&O or vendor literature and drawings?
B&O car superintendent John Tatum (during 1915-1941) had 64 rolling stock patents, which B&O allowed him to market under his trade name XLT (short for Excellent-Tatum). Conflict of interest concerns aside, these were available to be specified on B&O rolling stock orders and presumably off B&O as well. It is not clear if he received any royalties, from B&O or other, over or under the table.
Many Tatum XLT freight car parts only made cost sense on B&O, who made parts on the cheap from recovered salvaged feedstock (sheet, rods, etc.) at their Cumberland Forge. Tatum designed hardware and cost justified its use with this in-house capability in mind. Might not be worthwhile at another railroad or carbuilder.
Here are some examples:
- B&O wagontop boxcar and caboose design
- M-27B/F Tatum XLT roof for Evans foldaway auto loader ramps (Sunshine calls this a Mansnard roof, but that is a Loftonism)
- XLT brake step (simply folded sheet metal, no brackets)
- XLT rubber pads for passenger car trucks
- M-15j wood boxcar ends (once thought to be vendor Indestructable Ends, but these are actually XLT reinforced ends applied to many B&O wood boxcars of various classes)
- freight car truck designs, archbar and cast
- an endless array of brackets and widgets, many dozens, not all were patented
I have heard of "XLM" hardware in a Frank Murphy car design context. Speculation: since Tatum and carbuilder Murphy knew each other well, perhaps this XLM means Excellent Murphy as a friendly dig at Tatum.
I find myself saying that XLT hardware was B&O only, but I have not studied other railroads' rolling stock in similar depth; and thought this would be a good question to pose to this group.