Your thought-provoking question at another forum about switches I found to be rather strange. For decades most Santa Fe, now BNSF, turnouts that I’ve ever seen on the southern Transcon are of the No. 24 50 M.P.H. type.
On UP, 40 M.P.H. No. 20 turnouts are notorious on the Central Corridor, but over 13 years ago when revisiting the Central Corridor, new switches on the eastern end of the old UP were No. 24’s. It should be noted that a vice president that inspired the 40 M.P.H. turnouts and crossovers retired, and his successor apparently had different ideas about turnout speeds.
In your thread at that other website, a poster mentioned a 50 M.P.H. switch that looked like a No. 20 that was very ruff in passing over. There is a crossover switch on the Sunset Route at CP NORTH ONTARIO in the past that has been listed as 50 M.P.H. on the turnout route, but the tie count suggests it really is a 40 M.P.H. No. 20 one. As I’m not an official employee of the railroad, my observations need to be taken with a grain of salt!
Santa Fe installed No. 24's in 1959 on the newly constructed Williams - Crookton line change in AZ. I don't know if they had done this elsewhere.
There are plenty of #20 and #24 turnouts at crossovers and junction points....there are plenty of smaller turnouts still in the main tracks from #10 on up. In the name of economy of scale, UP-BNSF-KCS-CN-CP et al have all standardized their in-house design standards for AREMA Standards, usually #11 and #15 (formerly #10 and #14) on the mains and #7, #9 and #11 off the main tracks (formerly # 6.5, 8, 8.5 and 10 on ATSF, trying to stay away from 6 1/2 turnouts as much as possible from the 40' boxcar/end cab switcher era)....there will always be places where the new standard won't fit, so there always will a few oddballs around I still have nightmares about a #4 streetcar turnout in a street in the old warehouse district in LA.
(still cracks me up that there are plenty of luddites out there that think you just change the frogs and nothing else moves or changes to get instant speed increase. The 20's and 24's require a LOT more real estate to be installed... and then there is the moveable point vs. cast insert vs. rigid debate ....regardless, the welders will be busy fixing the wear and damage when they are not working the crossing frogs which see the most abuse)
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