A small "lathe" that clamps to the rail, with a manual cross feed taking ceramic inserts. The wheelset is jacked free of the rail. and the lathe clamped on, and the motor run with a welder as previously explained. We trued up the treads on the GEs at GLRR with this process many years ago, with the tool and a mechanic coming down from St Mary's River RR to do the work. It worked well, but ate ceramic inserts.

dave

Several days have passed since this flat spot event occurred, and I have heard some speculation as to how it happened. There are a lot of differing opinions as to the details, but the general explanation seems to be developing, and if true, it comes as quite a surprise to me. When I think of flat spots, I think of carelessness with the brake handling. Are we any closer to an explanation of the cause today than we were immediately after the event?

Well, aside from some sort of bizarre mechanical failure or giant slug of water, is there anything that will cause a steam locomotive's drivers to slide other than brakes?

And other than some sort of strange failure in the locomotive brake system, regardless of whether there was a service application or an intended or unintended emergency application, is there any circumstance where the engine brakes could not have been bailed off?

Some have said the diesel kept pushing. Maybe there was an MU box failure. That could explain the station overshoot and perhaps even a need to plug the train. It doesn't quite explain not bailing off. I think that's where we're at right now. People are not perfect and sometimes, especially under unusual circumstances, mistakes may be made

Steve

I think it likely that brakes were involved with the flattening, but a runaway introduces the good possibility that the brakes were excessively used intentionally, as opposed to carelessly.

Most of the speculation and controversy seems to be centered on what braking or other emergency procedures would have been possible in the case of losing control of the diesel locomotive such that it kept shoving at full power when it was not intended.

But aside from disagreement over how to stop the diesel, I have not seen any denial of the explanation that the diesel did unintentionally shove the train for a couple miles. If the flat spots were developed during that event, it seems quite probable that they were developed as a result of some type of braking scenario intended to hold the diesel from an out-of-control shove.

I would not rule out the possibility of mistakes being made in the use of the brakes. But if it is true that this was in relationship to a helper locomotive that could not be stopped, that strikes me as a very unusual added element to the flat spot event. It would tend to make the flattening a secondary issue in what went wrong overall.

There is another possibility: A panic-induced attempt to put the steam locomotive in reverse.

Even in the unlikely event someone did that, could it lock the wheels stationary?

Seems like depending on throttle, cutoff, and rail conditions, you'd either keep rolling forward against the force of steam or lose grip on the rail and rotate backward. Wouldn't it take a highly unlikely exact balancing of all forces to keep the drivers stationary? Seems like this is really grasping at straws.

I'm not an engineer but seems like unless a collision was imminent where you need every bit of retarding force, flat spots be damned, you'd keep the engine bailed off regardless.

At this point, unless some new facts come out, we should leave the speculating to the fan forums.

Steve

If you put it in reverse and open the throttle, the drivers will stop turning for a second or two, then try to start turning backward, assuming the rods don't fly off from the sudden shock. Enough to make flat spots. Not big ones, but flat spots nonetheless.

This video shows the Mt Pleasant “run by” as well as grinding and test run in HD. You can hear the diesel was not attempting to power down up all the way through the station.
http://www.youtube.com/watch?v=j9ukJHWUuhQ

The steam tracker is off, just notices on where the rest of the train is going with the E-9s. Rumor has it 844 is heading for Georgetown TX, north of Austin for the wheelwork. GREX?

From all of the discussion I have heard about the braking arrangement and M.U. control between the steamer, the diesel, and the train, there is lots of speculation and controversy about what action was taken or could have been taken.

But what does seem to have been established is that they lost control of the diesel and it propelled the train for a couple miles against the intentions of the crew. That seems like a fairly big deal if it is true. I think the technical explanation of what happened will be very interesting.

And the event recorder download from the Diesel should tell the story.

PC

Is it possible to open the diesel's throttle when you actually meant to use the diesel's dynamic braking?

You can't do dynamic braking with the MU box. Only throttle.

This video in slow motion is scary as you can actually see the brake cylinders appear to be fully applied. http://www.youtube.com/watch?v=O2gvqm1AIXs&feature=relmfu

I absolutely wouldn't want to be at the throttle in that situation.

Yes, was once possible. I am not sure about all diesels in that regard. That did occur with that CSX runaway train somewhere down in the central U.S. (Ohio?) maybe ten years or so ago. I also read about that happening on the D&RGW in a book called, Call the Big Hook. That one led to a derailment. I understand that with this U.P. incident, the diesel had nobody on board at the time. I do not know how the diesel helper is normally controlled from the steamer. I assume that it is quite a specialized system. It would be intersting to see a complete explanation of how it works.

I remember when the Clinchfield ran their little 4-6-0 with a homemade M.U. controller in the steam locomotive to run a pair of B-unit diesels.

If there was nobody on board the U.P. diesel, was it not possible for someone to get to it by passing over the tenders of the steamer? Aren't there some type of running board passageways on the tenders?