Not clear what your sentence "at least one axle has tires" means.

For those of you curious, here's a photo of the MU control box in UP 844. Taken April 2010.

Zak, thanks for posting that. It is many years since I have been on 844 and I did not remember all the features. The box is all standard EMD components, looks like the diesel box designed by Bruce Meyer. Notice there is no MU shutdown position on the throttle rotary switch, that function is probably provided by the switch at lower left.

Once again, the download from the diesel will tell what happened. It will show exactly when the brake application occurred and whether the PCS functioned properly, as well as the time delay. It will also show whether the application was bailed off or not. It will show the live feeds coming in on the trainline so if there was a component failure in the diesel box it should be evident. It will also show exactly how the diesel was powered down, whether by shutting off generator field or by putting the isolation switch in isolate. There is very little on a computer controlled diesel that does not get monitored and recorded these days.

I take the fact that the diesel was left running when they backed into the yard to have some significance. If you just had a runaway with a computer controlled locomotive, you would shut it down and then pull the battery switch so it could not autostart (if equipped with that feature) and do anything else. That they left it running might indicate that the crew had found the cause of the problem and were not afraid of having the locomotive do anything unexpectedly.

Following up on John's posting, it is my understanding that 844 does have a mountain cock, allowing the driver brakes to be selectively cut out so that they do not apply.

PC

Why after 7 pages of commentary...has someone not just asked the Union Pacific what happened? Or, contacted TRAINS magazine...they typically have the ability to communicate with railroad companies for information. Endless speculation just drones on, and on, and on, and on.

The videos on YouTube are interesting for sure. The engine hasn't been catastrophically damaged...trips have utilized other pieces of UP equipment...the "stair car" was a victim of a yard accident...etc. All of these are unfortunate events...but, life will go on.

To Union Pacific...thank you for working so hard to allow all of us to enjoy your proudest moments with the UP Steam Program...and we support you all the same when things happen. See you on the road.......

Do you really think that the UP officials who are in a position or situation to know exactly what is amiss here, even the ones who may be on a first-name basis with certain parties on this forum, are going to come right out and tell us exactly what happened, even as the matter is most likely being thoroughly investigated by UP's own forces? The number of parties in North America that are in a position to need to "compare notes with" the UP on this--as in, fret about diesel-locomotive controllers in steam locomotive cabs and their electrical and/or mechanical operations--totals about five nationwide (3751, 261, Norfolk Southern, Grand Canyon, Ross Rowland....), and UP doesn't even owe them any consideration whatsoever except out of benevolence.

We're lucky that this didn't somehow become an incident that involved NTSB investigation (and it may still come to that). As far as I can tell, we happen to be lucky that this didn't involve, say, a public excursion that ended up blowing a red signal with serious results. Whether this is an issue of mechanical error, operator error, mechanical failure of parts, or logistical error, the railroad deserves the chance to figure out what it was, and how to rectify it or prevent it in the future.

It's not too preposterous to say that the future of the UP steam program, and maybe even mainline steam in North America, could hinge on what comes out of this investigation. I hope that's a grotesque exaggeration, but it only takes one reporter asking the wrong question of the wrong executive, one board member raising one salient point in a meeting, or one insurance company professional reading too much between the lines of this discussion, and 844 and 3985 could go cold for good. Given that, until such time as someone presents hard evidence of a cover-up conspiracy involving safety issues with this program, they deserve to be left alone to take their time and do a proper investigation.

It's entirely possible that a bunch of flat spots on drivers may well be the "least awful" option that could have come out of the situation in question.

Has the 844 been upgraded to a 26 style system or is it still 6?

Neither. It is 8ET, as when it left the factory. So is 3985.

And neither of the trailer truck wheels has tires.

The so-called "mountain cock" cuts out ONLY the driver brakes. The trailing truck and tender brakes continue to function, as do engine truck brakes on engines so equipped (most don't have enguine truck brakes in the first place).

Think about it: Why on earth would you want one valve to be able to cut out the brakes on the whole thing? Imagine that happening on a light-engine move, such as a helper returning down the hill by itself. That is why it's not an all-or-nothing valve.

I do see the brakes set on the trailing truck and tender of 844, on both auxiliary tenders, and on the helper. So the entire motive power set has brakes set except for the drivers on 844. So there must be a way to cut out the driver brakes while the independent is set.

Here is a scenario that I think fits:

A service application was made on the whole train (except the drivers of 844) to see if it would slow down. The engineer refrained from dumping the air and dynamiting the brakes into full emergency because he was worried about flat spots on all the cars if the diesel kept shoving or at least prolonged the stopping distance.

When it became evident that the service application would not overcome the pushing diesel, the engineer added the driver brakes of 844 and inadvertently slid the wheels. But it did slow the train enough for a crewmember to get off and either board the diesel or trip the emergency fuel shutoff.

6 or 8, it doesn't matter, it does answer my question. I suspect this is a good time to end this discussion for a number of reasons.

As info, 4449 also is equipped with 8ET.

Where can I find a refresher on how these brakes are different?

Yeah, I could use a primer on how 8ET differs from 6ET. As far as I know, 6ET couldn't train with anything 24 or later; the independent was handled differently. 6ET (and 14EL, for that matter) piped all the independents together, releasing the independent blew all the air from all the units back through the controlling units brake valve. 24 and later used relay valves on each unit. There was a 6 variant that could MU with either 6 or 24; the schedule eludes me at the moment. If 8ET didn't make use of relay valves (and I don't see why it would have, it was still a steam era schedule) then something has been modified if the 844 can properly train with the current 26 equipment on the diesels.

From the factory, 8ET had pressure maintaining. 6ET didn't, though it probably could be retrofitted (a lot of 6BL systems were, for example).

When equipped with the proper relay valves and break-in-two protection valves, 8ET will MU with 26L, 30ACDW, CCBII, and the many derivitives of these various systems. It also has a P2A penalty valve to handle overspeed, cab signal, and ATC violation situations. It does not have automatic sanding, but a trailing diesel unit will take care of that function for itself.

When so equipped, the 8ET equipped steam locomotive has an independent actuating and release pipe (or brake cylinder equalizing pipe as it is known in some circles) and an actuating pipe. I think you will find that both UP engines and SP 4449 are equipped as outlined. These systems have performed trouble-free for 3 decades or so.

I had a thought today on the original subject. While this may seem to start out a bit off topic, bear with me, please.

On vacation some years ago, I wound up invited down into the engineroom of a brand new double-ended 'egg-beater' ferryboat, in service for about three weeks. (I never turn down that kind of invite!) The engineer told me of an incident that had happened with this boat's slightly older sister, a few weeks before. While docking, the master lost all control of throttle and direction, and they kissed the slip a little too hard. Fortunately, there were no injuries, and only minor damage to boat and slip. The master was able to call the engineer by phone, and the engineer shut down main prop from his station in the engineroom.

What had happened was that all control from the pilothouse to the engineroom was by way of fiber optics, and that one of the connectors had shaken loose! There apparently was no hard-wired E-stop circuit. (My background is in industrial automation, and big red Allen-Bradley or Square D mushroom pushbuttons are a way of life in that business).

Now, I've been collecting locomotive operating manuals and wiring diagrams since I was in high school. Two or three years ago, I purchased an AC 60000 wiring diagram on eBay. It would take me awhile to find it, but IIRC there were six (6!) computers, linked together with fiber optics. When I got that diagram, and started to study it, my thoughts immediately went to that ferry incident. I wonder if something like that happened with the 1892; and yes I know its an EMD.

Again, we won't know until the event recorder is downloaded, and as ADM IV stated, UP may not be too willing to share any information on this. And not to beat up another poster, but the 8ET has been around since the FTs, at least. Twice thirty years and then some-

And here is another aspect to consider. Many of the "diesel boxes" that are out there are now over 40 years old and are antiques in their own right. A friend who is very well informed on the availability of older locomotive parts tells me the rotary throttle switches used on some boxes have been out of production for some time. Some of the boxes were probably built prior to the availability of exane wire, and insulation on control wiring from the 1960s often falls off the wire in chunks if the wire is moved to replace a component. How many diesel boxes have been rewired with modern locomotive grade control wire? How many organizations running them have accurate records of the maintenance that has been done? Some of the commuter agencies I have worked with would have great concern over having to operate a locomotive in passenger service with control wiring that is this old. So this is both a concern and a potential safety issue, perhaps one that should be discussed by industry organizations.

PC