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My 13 year old son is doing a science project. He is trying to develop a paper that analyzes the significance of different diameter drive wheels on steam locomatives regarding speed and hauling loads. Any ideas regarding sources he might check?
Thank you
hankmorris Member # 1956
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Large diameter wheels found normally on passenger locomotives. Bigger the diameter, the faster you go. Traditionally, small wheels were for freight. Hope this helps.
------------------ Hank Morris, consulting editor National Railway Bulletin (NRHS)
atsf3751 Member # 1538
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To elaborate a bit, yes, large-drivered locomotives were often used for passenger service, and large drivers were normally used for speed. However, as the steam era progressed, larger drivers became the norm.
For example, the 4-8-4 was designed as a dual-purpose locomotive, and many had very large drivers. Engines like 3751, 844, and 4449 all had 80-inch drivers and hauled both passenger and high speed freights. The Santa Fe had a class of 2-10-4 freight locomotives with 74-inch drivers, rather unusual for a strictly freight locomotive.
Most freight-only locomotives had drivers with diameters less than 70 inches. Speed was not a necessity but adhesion was, and larger drivers are prone to slipping under a heavy load.
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