Eastern Railroad Discussion > What happens in the cab leading up to and after a stall?

Hello.  I just watched a video in which a CSX train stalled on a grade.  Questions for the engineers out there, please.  What does the engineer see on his instruments in the minutes leading up to a stall?  Does the engineer bring the train to a stop in response to instrument indications, or is the stop automatic because the locomotive control system senses the problem and takes action?  What actions are required immediately following a stall in order to stabilize the situation and protect the train?  And finally, how does the train dispatcher manage the recovery of a stalled train? Thanks for reading this.  Hope to hear from some nowledgeable folks.

Obviously you see your speed drop till it shows 0.01 mph , sanders on, sometimes a little independent to keep the wheels from slipping, your amps or reactive effort start maxing out, the accelerometer showing big negative numbers till it finally stops showing anything at all and your conductor looking sick if he’s even awake.

Usually you don’t give up till the train stops itself (when it stalls the engine doesn’t stop itself due to anything computer related usually, it just can’t pull anymore) or your traction motors are about to overheat (non AC power), then you set the air brakes up and let the DS know you stalled. Depending on the grade and local instructions the train might have to be secured (possibly up to 100%)
They’ll either have you double the hill or try to arrange for another train to cut off lite and come push or pull you up the hill.
Sometimes they’ll have you shove back and try to get a good run at the hill. Usually if we know that we might not pull the hill we run a little hot speeding by a few MPH to try and give it a better chance of not stalling. That’s harder to do now with PTC, you can only get 4 over cus at 5 it stops you and the RR likes to fire for PTC enforcements.

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Edited 1 time(s). Last edit at 10/28/19 21:36 by jointauthority.

Throttle handling is at the engineer's discretion but he needs to mindful of monday morning qb rfe's that will review the download. If he shuts off the throttle too early, he may be accused of intentionally stalling the train but if he waits too long, wheel slip and surges in ampereage could cause a broken knuckle or worse. The next thought is stopping on the grade ideally while keeping the train stretched.

I've always wondered about the "post stall" search for the guilty.  In these days of a constant search for someone to fire, does the question of "Who decided how much tonnage to put on this train?" ever get asked?   I can sure understand why the conductor might wake up in a sweat, since he's the only soul aboard to handle the walking, handbrake setting, etc. that will be required.

jdw3460 Wrote:
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> I've always wondered about the "post stall" search
> for the guilty.  In these days of a constant
> search for someone to fire, does the question of
> "Who decided how much tonnage to put on this
> train?" ever get asked?   I can sure understand
> why the conductor might wake up in a sweat, since
> he's the only soul aboard to handle the walking,
> handbrake setting, etc. that will be required.

Typically there is only so much the train crew can do to prevent a stall. So unless it's obvious the engineer did something wrong handling his/her train, they're in the clear. Just about every factor is out of their control. 

I have seen local supervision get in trouble for trying to 'risk it' - instead of adding power/pushers to an over tonnage train - resulting in a stall. 

Places where you COULD stall should be well known, and the amount of tonnage and power that can be used should also be known. What goes wrong is the failure of management to understand that a motor with axles cut out, and generally worn out CANNOT make it's rated tonnage in any way shape or form. Yet they say take it like you got it. And you being intstructed proceed and go as far as you can. Since you DID point out the problems you generally will not be held to account if the inevitable happens. 

A lot depends on whether the units are DC traction or AC traction. With DC traction motors, the Engineer MUST be mindful of the short-time ratings for his/her unit consist.

For AC traction motors, assuming the consist is ALL AC units, on hot summer days, the traction inverters will "power lime" and slowly reduce the power to all the AC traction motors. I have experienced quite a number of such instances with BN/BNSF SD70MAC consists, where the speed just drops off to 1 MPH, on the grade. At that point, the Engineer sets the air and stops the train (also telling the additional maned pusher/helper on the rear. Then, with the train stopped, center the reverser, and rev up the engines so as to cool the inverters ( by using the appropriate computer screen, the actual temperatures of the lead unit's inverters can be monitored). After about 15 Min of cooling-down, the units will all be back to full traction power, and are ready to re-start the heavy coal train.

Since the entire consist (including the pusher/helper on the rear), the reverser can be returned to forward, bring the throttle up to about run 6 or 7 (depending on the grade), and with the independent brakes still set, release the air on the entire train (with a DPU in the rear, the brake pipe will pump back up fairly quickly). As the train brakes release, the units will ever so slowly start to creep forward, at that point begin modulating down the independent brakes, and place the throttle in #8. The entire train, with help on the rear, will ever so slowly begin to accelerate back to the 10 MPH balance speed on the grade.

There is NO WAY such an action could be accomplished with DC traction motors, as in the stall condition, the copper commutators will seriously overheat and burn (referred to as 'stall burns').

In my expereince the initial actions during the leading up part were many, many, many cuss words. And right after a stall there were many, many, many MORE cuss words... ;^) Especially when a stall was caused by management trying to get every last nickel's worth of tonnage out of the available horsepower...

Lance/199

At my away terminal going east is a steep departure and going north is likewise steep, so pushers are on duty around the clock....albeit doing roustabout work when they aren't pushing... Many of the eastbound trains now can make the hill as they are since the latest AC motors are super heavy and have great adhesion....then add DPU and so on....but stalling happens often enough, that one only has to holler at the yardmaster and say "we stalled on devils curve"....that fairly tight right hand curve that will kill a train that isn't going to make it. "OK, I'll get the pushers behind you, stand by......." all is hunky dory, but when you get farther down the road and put your train away, you're motors will be downloaded and the camera roll viewed, to see what info can be gleaned.....then if your story lines up with what the download says, they just chalk it up as another day on the railroad.....a grade is a grade and sometimes you just can't climb it. 

I used to dispatch the NS line north out of Columbus, Ohio. You might not think of grades there, but most lines to the north have a good climb out of the river valley downtown. This would be the current Weber Connection. When a train stalled, I would tell the Chief Dispatcher, and we'd discuss a plan to get it moving quickly. Usually, the engineer would know whether to back down and attempt another run at it, or if more power was needed in some form. A shove would mean protecting the rear of the train, so a ride for the conductor would be needed. The most common scenario to get moving quickly would mean finding a crew with power to shove the train up off the hill. Often, that would be Weber Road. So, either have a following train tie down, cut their power off and go shove the stalled train, or talk to the trainmaster about a yard crew going out to do it. Then, when they get up the hill and cut off, the light power needs to have a route back to where they came from. Then we have to gather any information related to the cause of the stall: engine problem, wet rail, bad signal, or whatever. As discussed elsewhere, if management thought there was an issue with train handling, they would investigate that. Often, we were instructed to ask the crew some questions on the radio to aid in this. Regarding DC traction motors, we often heard the term "bird-nesting", which meant the copper windings got so hot they got soft and the rotation caused the coils to come loose off the rotor. That was a rare event, though.  

I stalled recently , got down to 3 mph and stopped the train there was just too much hill left. We hadnt started trying to dig through the rain to china but it was fixing to happen,  My tapes were remotely downloaded and i was questioned as to why i stopped pulling and told to pull till she smokes or burns the rail next time. 

NSDTK Wrote:
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> I stalled recently , got down to 3 mph and stopped
> the train there was just too much hill left. We
> hadnt started trying to dig through the rain to
> china but it was fixing to happen,  My tapes were
> remotely downloaded and i was questioned as to why
> i stopped pulling and told to pull till she smokes
> or burns the rail next time. 

By golly if they told me that, I would put it in my little black book and be darn sure the rail came in two by the time the wheels stopped spinning then next time!

NSDTK Wrote:
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> I stalled recently , got down to 3 mph and stopped
> the train there was just too much hill left. We
> hadnt started trying to dig through the rain to
> china but it was fixing to happen,  My tapes were
> remotely downloaded and i was questioned as to why
> i stopped pulling and told to pull till she smokes
> or burns the rail next time. 

A typical response from today's know nothing young railroad managers!  

halfmoonharold Wrote:
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> ... Regarding DC traction motors, we often heard
> the term "bird-nesting", which meant the copper
> windings got so hot they got soft and the rotation
> caused the coils to come loose off the rotor. That
> was a rare event, though.
 
I heard that term "bird-nesting" a good bit on the Santa Fe working power distribution, usually about a bad order unit on the Transcon. "Traction motor unwound" was another common term. Must have been a speed thing.
 

Any dc motor that is a sd60 or a dash-8 or newer will derate its self. This includes the gp 49 and gp 60 too.That is usually when a stall happens.

oneblock Wrote:
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> Any dc motor that is a sd60 or a dash-8 or newer
> will derate its self. This includes the gp 49 and
> gp 60 too.That is usually when a stall happens.

Uneccesary derates sure will cause a stall....then newer AC's have better anti slip programs and they will somehow keep pulling even while derating....but at some point....you're all done. 

ts1457 Wrote:
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> > ... Regarding DC traction motors, we often
> heard
> > the term "bird-nesting", which meant the copper
> > windings got so hot they got soft and the
> rotation
> > caused the coils to come loose off the rotor.
> That
> > was a rare event, though.
>  
> I heard that term "bird-nesting" a good bit on the
> Santa Fe working power distribution, usually about
> a bad order unit on the Transcon. "Traction motor
> unwound" was another common term. Must have been a
> speed thing.

When it occurs, that axle locks up and the wheels slide. That involves developing a flat spot, then aggravating it setting it out.

A couple of interesting such: https://www.trainorders.com/discussion/read.php?18,4818871,4820792#msg-4820792 Date: 07/01/19 13:16 Re: You've got to be kidding me! Author: TAW

TAW

I remember an old head telling me once, it won’t pull shame on them. If it won’t stop shame on me.

Posted from iPhone

I remember being in the cab of Southern E8 6901 shortly after it was donated to the Atlanta NRHS (and before the SERM moved to its current location). The rear prime mover was down, and to make a long story short 6901 was being used to switch cars. The old museum site had a significant grade. Well, 1200 hp into axles that were geared for passenger train speeds pulling a string of heavyweights up a grade from a standing start... not a great idea. After running in the red for a while, you could smell and feel the heat coming up from the traction motors under the cab. 

oneblock Wrote:
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> Any dc motor that is a sd60 or a dash-8 or newer
> will derate its self.

I had a train with an SD60 on the point slip down and stall on snowy rail between Merritt and Berne in the (BN) Cascades. The way the engineer described it to me, he let it go until the SD60 turned itself into an SD7, then put it out of its misery, shutting off and backing into Merritt. We came to the same conclusion: put the SD40 on the point (manual sanding) and go.

The power bureau guy yelled at me. It was unnecessary. Weather doesn't affect locomotives; the engineer (one of the best I've worked with) just didn't know what he was doing. Beside that, we don't want engineers tearing up our rails using sand on those old manual sanding locomotives.

TAW



Edited 1 time(s). Last edit at 10/30/19 14:56 by TAW.