Side elevation of a Baldwin-made 4-6-0 made in 1860. Note the decorative head light and drive counterweights. What this drawing was intended for isn't clear but the draftsman made a mistake. Look where the main rod meets the side rod. It seems to have been installed inside the main rod, which would prevent a full rotation of the wheel. Apparently no one checked the drawing before it was published.
2 comments:
I'm gonna play devil's advocate here. It would have been uncommon (very) to mount the connecting (main) rod inboard of the coupling (side) rods, but I can visualize the wheel fully rotating because the connecting rod is mounted to a crankpin and each part moves within it's own plane. The connecting rod should clear the hub in the same way the coupling rods would if they were mounted traditionally. My guess is the connecting rods were traditionally mounted outboard because they were the parts that bent or broke and the outboard location would make trackside replacement much quicker.
That said I don't know why this one would be different...Baldwin was on the leading edge of tech in his day and maybe you can apply more torque to a shorter crankpin? Or it could be a mistake but I can't imagine everybody missing it.
I couldn't find a 6-wheel but here are few images of inboard connecting rod mounts:
https://readingroo.ms/5/1/9/7/51976/51976-h/images/p030.jpg
https://www.thehopkinthomasproject.com/TheHopkinThomasProject/TimeLine/IndustrialRevAmerica/SteamEngines/JohnWhite_files/image078.png
https://www.thehopkinthomasproject.com/TheHopkinThomasProject/TimeLine/IndustrialRevAmerica/SteamEngines/JohnWhite_files/image009.png
I might be missing something in my visualization; by all means let me know.
I dunno — see the photo of an 0-6-0 at an earlier post:
https://progress-is-fine.blogspot.com/2026/02/wapwallopen.html
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