I have noted a general habit of modellers to equate a ribbed-back wheel with a cast iron wheel, so I went seraching the archives on the Steam Era Freight Car List to see what I could learn. The following information comes from posts there by such knowledgeable modellers as Richard Hendrickson, Tony Thompson and Tim O'Connor:
1. Ribbed back wheels do not always signify cast iron wheels - some forged (wrought) steel wheels had ribbed backs and some cast iron wheels had plain backs. The proportion of cast iron wheels with ribbed backs was much higher than for wrought steel wheels.
2. Ribbed wheels, as such, were not outlawed! What was banned - in stages - was the use of cast iron wheels.
3. Cast iron wheels were banned in new car construction in 1958.
4. Cast iron wheels were banned as replacement wheels in 1963.
5. Cast iron wheels were banned in interchange service in 1968.
The ARA (later AAR) adopted a standard for wroght steel wheels in 1917. According to the 1946 Edition of the Car Builders' Cyclopedia, 80% of freight cars in service at that time were equipped with chilled (cast iron) wheels. By the 1953 Edition of the Car Builders' Cyclopedia, that number had dropped to about 2/3 or 66%. Based on this information, those of us modelling the 1950s and early 1960s might want to have somewhere between 30 - 70% of our cars equipped with a representation of a cast iron wheel. From a modeller's perspective, the most obvious distingishing feature would likely be a ribbed back!
Cheers,
Greg Kennelly
Burnaby, BC
