> Late 1940's, Union Pacific.

OK

> So tell me what 'your' railroad was doing to
address the "issue" at that time.

SP. I don't have anything from that era, so I can't give details on how the SP got the word out then. I saved all my ETT, SSI, and TTBs for the period of 1974-1996 (not to mention air brake rules and train handling instructions). They have many stipulations about specific SP-owned cars having speed and/or handling restrictions. Obviously this couldn't be done for all the other RRs, which had tens of thousands of freight cars at the time. The thing about the 45 mph speed limit for empty bulkhead flats was also there, although not SP-specific. Occasionally there would be a notice about problems with off-line cars. Thus, I suspect that the SP followed similar practices when the CI wheel problem became apparent.

Then again, when I was at the SP, they bent over backwards to make sure you had access to all the information you needed to get over the road safely. Not all RRs did this. Usually it is the conductor's job to ascertain whether there are restricted cars in the train, not the engineer's.

CI wheels went away in the 1950s because of the weight/speed/catastrophic failure thing. Once the RRs figured out what the problem was, they would have informed you one way or the other not to exceed a certain speed with them in your train. How this was accomplished varied from RR to RR. Today's maximum freight speeds revolve around empty or loaded, as well as maintenance expenses to cars and track. Figuring into this is that empty freight cars have an annoying tendency to become airborne when train speed starts exceeding 60 mph, particularly empty autorack cars.

If you'd like, we can go on to discuss the problems with three-riser wheels, straight-plate wheels, and putting composition shoes on brake systems designed for CI shoes.

To get back to earlier comments and posts, it doesn't matter what the capabilities of the locomotive are, the speed any given train may operate is determined by the slowest car in it. This means that a 75 mph capable steam engine (of your choice) hauling freight cars which have an RR-imposed speed limit of 45 mph may not go any faster than 45. If you do, you might get fired for speeding.