Why did the slip go on so? Why did the driver try to center the valve gear (and wound up breaking both arms) instead of closing the throttle or regulator?

In any event, I'm glad the injuries apparently didn't prove fatal to either driver or locomotive, and while I know the engine is back, I also hope the driver came back, too.

I have no reason to doubt the veracity of the report....but similar conditions can oocur if there's high water, foaming carryover, and a lot of superheater area between the dome throttle and the valves in locomotives so equipped. I have no idea how Blue Peter is set up. In that case, closing the throttle won't stop steam flow until all the expanding superheated water has flashed, and run through the system......so centering the reverser and opening the cylinder cocks would be the only response. I wouldn't think it would go on for anywhere near so long.......holy crap.

dave

As someone who's actually trained in emergency "defensive driving" and actually escaped a potentially harrowing accident because of it:

Your car suddenly has a stuck accelerator. Do you try to pull up on the floor pedal, turn the car off, or pop it into neutral?

Those who have had to control a conventional rod-and-piston steamer (as opposed to a geared steamer) working at maximum power can testify that the control of the slippage is made on the "Johnson bar," not the throttle. We have a regular on this forum who used to run big 4-8-4's on steep mountain grades with an occasional slip; let him chime in here.

The problem with the A2 Peppercorn Pacifics (and several other non-North American passenger steamers) in this regard is that they had screw reverses, akin to the famous "steering wheel" in the CP Royal Hudsons and some other steamers. Those allow for a higher degree of precision in valve setting, but are a royal pain for having to make adjustments quickly, such as switching or arresting a slip.

If the slip is from a stuck open throttle or a collapsed dry pipe or something like that I would agree that centering the engine would work.
If it's not from something like the above, the close the throttle! Nothing you do with the reverse leverr is going to do any good.
I'm thinking that's what you meant.

A stuck throttle doesn't cause the slip; it only screws up your ability to do something about it. Virtually every time wheels spin, be it locomotive or automobile, it's too much power for the amount of traction available, not from an out-of-control throttle. On most steam locomotives, it's easier and quicker to adjust the valve gear than the throttle.

I would suspect that by the time the engineer in 60532 figured out what he was up against in this incident, he was dealing with two broken arms instead of the throttle..........

I agree with Frisco1522. If an engine completely breaks loose in a spinning wheel slip, close the throttle and get the engine back on her feet, apply sand, then reopen the throttle and go on. Adjust the cutoff as necessary with the engine working normally. Trying to control a serious wheel slip with the reverse is not a practical idea and may actually increase the slipping at first.

Even if it is caused by a slug of water in the superheaters, which I have experienced several times, you still want to close the throttle first. Then center the reverse to control the power, if necessary. The steam generated in the superheaters will expend itself quickly enough, although this can be a disconcerting experience.

The "Hand on the throttle" pose is not just a cliche. Engineers handling engines working on heavy grades commonly run with their hand resting on the throttle to be ready to close it at the first sign of a slip. If the engine has a true "Johnson Bar" (manual, not power reverse) the last thing you want to do is unlatch the dog when the engine is slipping. The bar can instantly become uncontrollable causing you serious harm.

This reminds me of an engineer I worked with on the D&S years ago. He had a habit of setting the throttle and sitting back relaxing with his arms crossed. If the engine would begin to slip he would just calmly reach up and turn on the sanders and wait for it to catch again. (Not a practice I recommend.) The K-28 class engines we were running rarely completely broke loose all at once, but would usually just start slipping gradually, so this worked well enough, usually.

One day someone greased the rail for us on Hermosa hill, a 2 1/2% grade. The engine went immediately into a complete, uncontrolled, wild screaming frenzy. By the time he closed the throttle and got things settled down again I had bailed off the seat and was standing in the middle of the cab in case a side rod came through the floor.

Thanks for posting that video and photos, I'd heard of it but never saw any of this stuff before.
I had a train fan video years ago of 2716, watch this around 3:07 to see a really long wheel slip: http://www.youtube.com/watch?v=_Ia2Ok9Phaw
I've often wondered why they let it go that long, and what the story was?

I remember reading somewhere that this incident was partly to blame on a driver who was not familiar with the locomotive, and thus let the situation get out of control due to his inexperience.

That's how the Wikipedia article on Blue Peter said it:



I don't even want to think about what might have happened if someone had been standing next to the engine when this happened.

A stuck throttle can't "cause" the slip, but if it sticks open and the engine slips it's going to make matters much worse really quick.
Sanding a slipping engine is a serious no-no. It's wrong in so many ways. Could slip a tire, damage drivers or a driver if it's already on the border of being loose on the axle and mess up the valve gear.
You have to get the slip under control first, then sand. Big difference.
I would think carryover would have bled itself down but in the video, it didn't look like the steam supply lessened to the cylinders even after they broke.
Had to have been something with the throttle or a collapsed dry pipe or something like that.
Or cockpit error.

The account in the typically-notoriously-questionable Wikipedia cited by Brother Yerkes matches everything I read post-incident in several accounts in several rail magazines from the U.K. shortly after the accident:



Read it until you comprehend. It looks like it may take you a few more tries, or that you are determined to stick to your ideas in spite of any evidence presented otherwise.

If the valve gear is brought closer to center, the piston is getting short bursts of high pressure steam. When closer to the corner, the piston is getting more even steam distribution. Do the short bursts of high pressure steam decrease the amount of power applied to the rail at all/enough to help control slipping when there is nothing preventing the throttle from being shut?

While at college, I met a former LS&I engineer. He told me that one time he a throttle stick open on his engine. He said he opened the cylinder cocks, centered the valve gear and applied the independent.

I've spent my fair share behind the throttle of a few lokis the last 20 years and every slip I encountered, I've arrested with tactful throttling action followed by conservative sand usage. Never once have I even thought to grab the reverser, and I can't even fathom trying to wind one as in the case of the Blue Pete. Mind you, I was not in the same situation as the BP with high water/carry-over.

I can see, however, if the BP was superheated, that will a full bottle all that water filling the dry-pipe and flashing to steam in the units could be a self-exciting matter that wouldn't stop by simply shutting the throttle, in which case the only option would be to center the valve gear, open the cylinder cocks etc. etc. I have in some cases run into situations (albeit not foaming situations) where domed locomotives will seemingly like to push their throttles open once they reach a certain equilibrium (I guess through back-pressure) after the valve gear was hooked up high enough and enough steam was being admitted to the cylinders. It wouldn't happen always, but if I'd set myself up running a certain way, my theory is that enough back pressure existed create a force that actually forced the throttle out and into my hand (there was a sizable force behind it). I've read that locomotives can reach this equilibrium where they almost begin to work against themselves given a certain speed and setting, thus the back-pressure I mentioned and it would make sense that the throttle could be forced open if a lazy engineer wasn't anticipating it. Combine that with wet or slick rail along with the BP high water situation, and you could have a run away really quick.

Never had the throttle forced open on me, but I have suffered from the superheater flashing over and the engine not wanting to do what I had intended for her to do. Fortunately I caught it quck and could get the cylinder cocks open and got it arrested. Once, when we were putting an engine away for the night, which involved filling the boiler as full as possible to have water to light off the next day...combine that with a small throttle leak and it was off to the races. Fortunately they got her stopped but it was a lesson never forgotten.

While I fully appreciate the theory of controlling a slip using the reversing gear, I don't feel that it is practical most of the time.

If you ever run an engine with a Johnson bar, the force alone of the valve changing direction that fast is simply dangerous to the engine and the engineer. Once I was on a trip where we were drifting out of town and the valve started to run dry. It was very sudden and the friction put out enough resistance to get the locomotive to start loping and nearly ripped the Johnson bar quadrant from the studs. It would have made sense to center the valve so it wasn't traveling but it would not have been a good idea to try and wrestle with it.

Johnson bars can be a bit cumbersome when adjusting the notches on a heavy grade and I would not ever teach a student to try to maintain control during a slip using this method. The theory? Yes. The practical application? I don't feel that it's a good idea. It's very helpful to understand all avenues of action that can be taken (like centering the valve on slips) and how they work, but practically it makes far too much sense to cut the source of the power (throttle) instead of trying to mess with the valve. Why?

What if you accidentally pull it back too far? You have an uncontrolled slip with steam still trying to do work.

A lot of engines are not perfectly square and centering them up is going to take some finesse that you may not honestly have in that instant. I understand that moving the valve to center is an effort to reduce the power being applied until the tractive forces are great enough to stop the slip, but a lot of times I'm already running the engine notched up as high as I can. Hooking the valve up is going to cause a whole lot of loping, and in my experience, uneven strokes can encourage the engine to slip further. I also feel the loping action is going to cause a lot more wear to happen to the engine as a whole rather than just the running gear. (As a side note, the 480 on the D&S has a slightly mismatched set of cylinders causing it to break loose far more often than any of the other K-36's. It slips out of nowhere on a sunny day because the power distribution is just never perfect. Whenever I hear about a running gear failure on the D&S, I immediately wonder if it is the 480 or not.)

Controlling the locomotive with the valve and a wide open throttle is ideal for efficient running, but when unfavorable conditions present themselves, you need to adjust and do the best you can to take care of the equipment and get over the road. Sometimes that involves compromising with the ideal technique.

In the case of Blue Peter, I'm sure that the throttle equalized and didn't shut off entirely because of the priming. It's hard to say because there is no video of the actual moments in the cab. I've had throttles open back up on me many times, sometimes it was just the nature of how the throttle had been rebuilt. You only learn how to deal with that through experience. I can not sit there and tell a student engineer how to be a good engineer. They have to familiarize themselves by doing it along with instruction. Knowing that the crew was inexperienced on that particular engine is more the fault of the system rather than the driver. How can you expect someone to know something when the teacher or system set up to guide that program has failed or has major flaws?

On the other hand, using sand to control slipping can not be entirely written off. In a perfect world you can control slips with the valves or wait entirely for the drivers to stop spinning before grabbing sand, but you can't pull that off on a mountain grade in wet weather or on leaf covered rails or the 30 year caterpillar infestation. You will simply lose your momentum and stall.

My experience is going to be different than Ross Rowland or Frank Collins or any other engineer. Most of what I have worked on has been steep, slow, narrow gauge mountain railroading. I've been on trips on the D&S with good engineers when we simply ran out of sand because of wet autumn leaves on the rail and we were hours late. It just doesn't work trying to shut off sand every slip with a heavy train and no momentum. You lose your momentum much more quickly at 12 MPH on a 4% grade than you do at 15 MPH on a 2.5% grade and so on. This summer in Chama we had major issues with caterpillars covering the rail from Cresco to the top of Cumbres, and full out dead stalls were nearly a daily event during the early part of the summer. I had a tonnage train on July 4th with a very slick engine and rain, and we were over an hour late to Cumbres because we stalled out more than 15 times. When you are going that slow, you have to keep sand going. I understand it's not perfect, but neither are the running conditions. Every engineer that I've seen run on the San Luis & Rio Grande, Cumbres & Toltec, Durango & Silverton, Georgetown Loop, and Dollywood Express would partially control slips with sand. (Sanding while throttle is cut down.) Those are all steep railroads pulling tonnage trains, not high speed trips with plenty of momentum or possibly diesel assistance.

I would like to submit some videos to back up some points I made. The first one is Reading & Northern 425 on a heavy train but what appears to be a fairly nice day. The rail seems to be slick though as evidenced by the amount of slipping. If you go to the 7:10 mark, the engineer does a nice job of shutting off and letting the steam cycle out (evidenced by the snifters) before grabbing more power... then it breaks loose again. Probably a similar scenario to the Blue Peter incident in terms of timing and actions taken in the cab, minus the use of adjusting the cut-off. It appears however that he was sanding after the first slip and when it broke loose again, sand is still running. He may have shut it off, but there is no possible way you can expect the sand to empty the pipe that quickly when things are happening that fast. It's just not a perfect world.

http://www.youtube.com/watch?v=vyTnLdgJ9T8&list=PLRQc6ZWg_CPq6_y8PhcxCWms5oMGovrm-&index=7

I'm sure many of you have seen the 611 stalling on Saluda. You can see dust from the sanders running when the engine stalls out. Again, they may have been shut off, but when you are crawling like that, you probably aren't going to make it. Go to the 3:30 mark. In a situation like that one of the only things you can do is get your water as high as safely possible for weight and manually sand the rail so you've got something under you when you get moving.

http://www.youtube.com/watch?v=NUPIynJq7tg&list=PLRQc6ZWg_CPq6_y8PhcxCWms5oMGovrm-

Finally, this is the trip I had with the 489 on July 4th. We stalled 15 times in 3 miles, but as you can see, the conditions are far different than the other two examples. We are going really slow (12 MPH track speed, we get to about 8 MPH in this clip) and the rail is wet. It is just not practical to go without sanding continuously or to start messing with the valve setting under those circumstances.

http://www.youtube.com/watch?v=b3aBrODrZF0&list=PLRQc6ZWg_CPq6_y8PhcxCWms5oMGovrm-

I very much appreciate this discussion and in no way do I feel that I have the absolute answer for an across the board technique that should apply to every engine on every railroad. I've not run a 4-8-4 at 70 MPH, but I have run a fair amount of the hardest working steam railroad miles in the country, so I can only offer my opinion from that angle. I do hope to learn something from those with different experiences.

Mentioning the 480, in this shot we were shoving back into Silverton and the slipping is controlled by pumping the throttle because there are no reverse mounted sanders. http://www.youtube.com/watch?v=_7lwXtVro6c&list=PLRQc6ZWg_CPq6_y8PhcxCWms5oMGovrm-