Charlie Vlk says:

Colloquial usage is just as important as correct technical manufacturer
designations from a historical viewpoint.

Perhaps. IOW, from a historical viewpoint, mistakes, erroneous conclusions and misuse of terms is as historical as correct conclusions and proper use of terms. OTOH, when one is standing out in -10� weather in Chicago...as shown in Ball's Decade of the Trains 1940s...checking wheels, wind blowing at 25, one might not worry about using the correct engineering terminology but use, instead, terms that he knew his fellow workers understood. One MIGHT even use non RR terms or words not found in most dictionaries but those which his fellow workers were well acquainted with as well. Possibly as it got colder, more of these words were used. There is no doubt that engineering and operational environments use, in many fields, different terms to describe the same thing. The STMFC is probably more in tune with the engineering side, being more driven by design and development than use...although both apply. Happily, it's not -10� here so I'm inclined to use engineering terms. However, during an op session...now that's a different story.

I have to chuckle about this at times, however. No less than Ralph Johnson, Chief Engineer for Baldwin Locomotive Works, refers to non roller bearings as "solid bearings" and "friction bearings" on the same page [ 185 ] in his book The Steam Locomotive. Maybe he was assuming that both engineering staff AND operations personnel might read his book <g>.

Mike Brock