Western Railroad Discussion > Slack action and DPUs

In regards to trains having DPU (s) is slack action much less of a consideration then trains that do not have DPU (s)?

I would expect the possibility of harder slack action with 2-400 tons of locomotive on the loose back there!  Take coal empties crossing the Palmer Divide at Palmer Lake, CO.  As trains reach the lake, slack is often stretched out with the DPs likely at a low throttle.  As the rear of the train reaches the summit, the headend is going into dynamic and the slack begins to bunch.  When the slack run in reaches the rear end, there can be quite the noisy run in.  With two units back there, it can be quite the bang if the DPs haven't been placed in dynamics, or when there are no DP units.

So, yes, slack must be on the engineers mind all the time!.

Robert

My home is within a quarter mile from Barnett on the east end of Cheyenne. Trains with DPU's still have some slack noise but it doesnt seem to be as loud as those trains without DPU's.

Bob Krieger
Cheyenne, WY

Yes. You don’t have to worry as much about slack when starting or stopping. (If you have a long or heavy train conventional you need to stop stretched out in lots of places to avoid the slack rolling out and risking a knuckle when starting.

It does bring its own challenge though, you always want to avoid having the DP come over a hill and run into you, that can be pretty violent if you’re not careful. Also you don’t want to be in too low of throttle on the DP when it hits a hill and you feel rear end get bogged down.

DP can be a pain in the butt on very hilly territory, especially with long train lengths because you tend to have communication loss with the DP and lose control of it temporarily.

If you lose comm the DP is supposed to maintain the last throttle setting for 90 minutes, but if you set air it will force itself to idle.

Thats supposed to only happen when you make at-least a 20 psi reduction but on some junky engines you set any air and the DP goes to idle immediately.
That is NOT good, especially since most trains with DP are long and heavy!

Edit: as far as double empties, i haven’t run them yet but I’m sorry if you can’t keep them together you’re probably doing something very wrong. It takes a LOT to break a empty coal train (unless someone really beat it up as a load and left you a partial break), I’ve had my DP put me into emergency from the rear multiple times running 60 on empties draped over some serious hog backs and it felt real rough but never broke.
Posted from iPhone



Edited 1 time(s). Last edit at 08/12/20 16:54 by swingnose.

swingnose Wrote:
-------------------------------------------------------
> ...
> If you lose comm the DP is supposed to maintain the last throttle setting for 90 minutes, but if
> you set air it will force itself to idle. That's supposed to only happen when you make
> at-least a 20 psi reduction but on some junky engines you set any air and the DP goes to idle
> immediately. ...
> ...

Disclaimer: I have been retired for over 5 years now but I operated mountain grade territory with undulating territory on the second half of the trip. The big thing is that I admit rules may have changed so I may not be accurate on everything.

First, if you're in "COMM LOSS" and you set the air, the DP units are supposed to drop to idle right then regardless of the amount of reduction. The 20-pound reduction comes in as part of the process to "normalize" the DP units for continued operation, which would require stopping. One thing is that although the DP screen may show "COMM LOSS", sometimes you will still maintain communication with the DP units and they will respond.

I ran with the fence up almost all the time, very rarely in "synchronous"; the only time I'd be in synchronous would be on the steady pull up the hill out of Oakridge (Oregon). It was also extremely rare I'd put the DP units in dynamic and would always have them pushing, even when I was in dynamic on the head-end. By knowing your territory, and I mean really knowing it, you can minimize slack by controlling the DP units properly. As a note, I also operated a lot of manned helpers before we got the DP units and that made it much easier because I knew what would happen "back there".

Railroads do not teach train handling. In fact they do not care about train handling provided you comply with rules. When I took students, which very was rare, I'd teach them lots of stuff they weren't supposed to know, such as power braking, train handling, how to use the fence to its fullest, all the stuff UP didn't want them shown. Looking at these ridiculous trains now I am very glad to be retired. 
 



Edited 2 time(s). Last edit at 08/13/20 19:31 by Railbaron.

Coal empties such as those at Palmer Lake will only have 1 DP Online. RPA restriction due to empty cars. If running synchronous which can be done cresting grade on an empty, the slack will adjust/stretch on the rear as power is reduced to idle.

10 psi brake pipe reduction is enough to come loss idle down remotes under basic conditions, but the rule prescribes 20 psi to ensure propagation under worst-case conditions, in particular with a less than fully charged train of the longer lengths more common today.

Posted from iPhone

If you plan your transition well, you don’t have any or much.

I work “undulating” territory and grade With 15,000ft manifest - and you can’t Always avoid it, but if you plan and use that counter you can mitigate most of it.

They are running mid and rear DP’s now in various configurations.

The energy management systems (LEADER/Trip Optimizer) we are required to use throw train handling out the window anyways so..

And no, it’s not used in any planning/train make up (slack action).

In any case, the counter and train list is your friend.

Posted from iPhone

MP683 Wrote:
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> ...
> The energy management systems (LEADER/Trip Optimizer) we are required to use throw train
> handling out the window anyways so..
> ...

Jeez, I forgot all about that stupidity!!! I only used it once and that was just playing with it on a small, overpowered train. I simply ignored it and never had a manager say anything to me about it. Then in December 2014 they changed the rules slightly making it difficult to not use it; so much for me running trains myself. I went in the yard at that point retired about 6-months later, once I had my vacation credits in for 2015. Glad I never used that ridiculous thing and even happier I never had to deal with PTC. 

Back when UP took over the SP, they did not want the engineer to put up a "fence" and run the DPU separately. Actually the best way to do it. I have no idea how other railroads feel about the fence.

HardYellow Wrote:
-------------------------------------------------------
> Back when UP took over the SP, they did not want the engineer to put up a "fence" and run the DPU
> separately. Actually the best way to do it. I have no idea how other railroads feel about the fence.

Eugene to Klamath Falls was one of the first areas on the SP to get DP units, the old C40/41's. Even UP itself west of Hinkle didn't have DP operations. But when they qualified us, a couple of people from Omaha came out to do it since nobody here was qualified, nobody ever said anything about not using the fence. In fact the guy who was with me even showed me the fence early in the trip. It does seem that I heard as the DP operations spread to other areas on the ex-SP lines they were pushing "synchronous only" for the most part but I used the fence a huge amount of the time and taught students brave enough to come with me how to use it to their advantage also.

Learn something new everyday, I know I’ve set a minimum on trains with comm loss and it hasn’t gone to idle but on some you touch the air and it idles.

The new LXA software is neat, it’ll put a message up when you’re in extended comm loss telling you that it will go to idle if you set air.

I’ve only been running for 3 years, almost 7 total on the RR so I’m still wet behind the ears lol

Posted from iPhone



Edited 1 time(s). Last edit at 08/13/20 11:15 by swingnose.

Enjoying the comments on DP operation.  Just wanted to make a comment about using the "fence" or not.  Where I use the term "RCE", I am referring to the old Remote Controlled Equipment terminology that was used prior to using DP.  On the old RCE 105 system on the Santa Fe they had a position labeled MU (multiple unit) or synchronous mode.  That would be "fence down" in today's lingo.  We always encouraged the engineers to not use it most of the time.  But they DID anyway.  To force them to operate the consists separately the MU position was eliminated entirely on the newer version of RCE called LOCOTROL II.  They then had to operate the consists separately (or with the "fence" up).  That continued until the modern DP (Distributed Power) came about.  I've been gone for over 15 years so don't know how the trip optimizer handles the trains now.

Some of Railbaron's comments on train handling were right on!   When my territory on the Lampasas subdivision got extended from Brownwood, TX to Sweetwater, TX I immediately went out to become familiar with it.  To learn the railroad I need to be in the driver's seat.  So here I am operating a loaded sulphur train eastbound between Sweetwater and Brownwood.  Of course I have my track chart with me.  Between Obregon and Bangs, TX there are several undulations so I have the lead consist in dynamic braking and the remote consist in a fairly high throttle position.  I hadn't noticed that the engineer, Jerry Hudson, had slipped over behind me, watching what I was doing.

Jerry commented that he hadn't ever seen a train operated that way, said he had always just used the MU (Synchronous) mode.  Said he was going to try my method.  A few weeks later I saw him again and he stated he had been using the method I used and was having a much smoother ride.  A lot of the older engineers hadn't ever been taught the proper way to handle distributed powered trains.

Whenever I would be riding a train I would always ask the engineer if he wanted to operate it the first half or second half because I was going to operate it half of the trip.  I would do this for two reasons.  One, I wanted to see how he operated it and second, I wanted him, or her, to see how I operated a train.......and then too, I always enjoyed operating trains (not sitting on the them, but running them............. 



Edited 1 time(s). Last edit at 08/13/20 11:25 by KskidinTx.

If you can run from Temple to
Brownwood, going all the way to Sweetwater is a walk in the park lol

Posted from iPhone

I agree.  I was already familiar with the Temple to Brownwood portion.  My little story was prior to interdivisional runs so the Brownwood engineers only worked Brownwood to Sweetwater or Brownwood to Cleburne.  Consequently the Bangs, TX area was their roughest part.
 

This is one of the best posts in months.

A buddy of mine runs on the other railroad and when I went it have lunch and told him where I was he said “drawbar alley”.

I looked around and didn’t see anything unusual on the railroad (road ran along the tracks).

I asked him if he used the fence and used the DP to push while the headend was in dyn.

They never taught it and no one used it.

He asked his engineer about trying it one day and he uses it every trip (on coal trains).

We have local rules that require the fence and not to put them in db in areas.

Took almost 10 years for the company to figure out that DP’s in brake 8 tend to anchor in dips and take knuckles with them...

Imagine that...

Posted from iPhone

Railbaron Wrote:
-------------------------------------------------------
> HardYellow Wrote:
> --------------------------------------------------
> -----
> > Back when UP took over the SP, they did not
> want the engineer to put up a "fence" and run the
> DPU
> > separately. Actually the best way to do it. I
> have no idea how other railroads feel about the
> fence.
>
> Eugene to Klamath Falls was one of the first areas
> on the SP to get DP units, the old C40/41's. Even
> UP itself west of Hinkle didn't have DP
> operations. But when they qualified us, a couple
> of people from Omaha came out to do it since
> nobody here was qualified, nobody ever said
> anything about not using the fence. In fact the
> guy who was with me even showed me the fence early
> in the trip. It does seem that I heard as the DP
> operations spread to other areas on the ex-SP
> lines they were pushing "synchronous only" for the
> most part but I used the fence a huge amount of
> the time and taught students brave enough to come
> with me how to use it to their advantage also.

In 2001 I traded seniority from LA to the Tucson Div. I ran a grain train from Tucson to Welton (just east of Yuma). I ran the DPU's separately all the way and was highly criticized for doing so. RFE informed me that Omaha wanted theDPU's ran in tandem with the headend power. Don't know anything about the Oregon Div. Maybe Omaha changed their mind's over the years.

HardYellow Wrote:
(SNIP)
>
> In 2001 I traded seniority from LA to the Tucson
> Div. I ran a grain train from Tucson to Welton
> (just east of Yuma). I ran the DPU's separately
> all the way and was highly criticized for doing
> so. RFE informed me that Omaha wanted theDPU's ran
> in tandem with the headend power. Don't know
> anything about the Oregon Div. Maybe Omaha changed
> their mind's over the years.

"Omaha wanted" is always a danger sign.  In any corporation, the HQ often has little idea about the reality in the field.

McDonald's Corp always fought with local franchise owners who would create their own meal deals, offer breakfast, etc.  Stuff that wasn't allowed, in big print. But, stuff that would  get people lined up to buy. And sell out.

Listening to experience is often a good way to run a business.  Any business.

HardYellow Wrote:
-------------------------------------------------------
> In 2001 I traded seniority from LA to the Tucson Div. I ran a grain train from Tucson to Welton
> (just east of Yuma). I ran the DPU's separately all the way and was highly criticized for doing
> so. RFE informed me that Omaha wanted the DPU's ran in tandem with the headend power. Don't know
> anything about the Oregon Div. Maybe Omaha changed their mind's over the years.

Actually, to my knowledge Oregon, or specifically the Cascade Subdivision (Eugene to Klamath Falls), was the first place on the ex-SP lines that got DP units basically so they could eliminate the helper pool out of Eugene. I don't remember the year but it was very shortly after UP took over. Our original DP units were old C40 and C41 units. SP did have some DP operations on the Rio Grande lines using C44AC units (300 series units SP bought) but I don't know of any other DP operations at the time on ex-SP lines. In fact even the UP mainline north and east of Portland had no DP operations and nobody was trained for DP operations, which got interesting when we had a tunnel fire near Cruzatte and they asked Eugene engineers to go to The Dalles so they could operate DP trains on the BNSF/Oregon Trunk. When UP started buying the AC4400 units, starting at UP 5700, they came here first to replace the C40/41 units. They then developed the CTE software and they spread everywhere.

The people who came to Eugene were from the "Technologies Department" in Omaha and were not operating people. They came here because there was nobody else who knew anything about DP operations so they came to "train" us. Basically they gave us a booklet to read before we started and then they came and our training was "on the job", i.e. we took a DP train over the road. I had the head guy with me and he had me do everything other than "Set Out Mode", including using the fence. At no time did any of the people here say anything about not using the fence and most of the SP guys, who were familiar with manned helpers, used the fence regularly. I used the fence almost all the time, virtually never let the DP units go into dynamic braking, and I never had anybody take exception to my using the fence. I also never had anybody take exception to my power braking either even though I did that a lot also.

What happened on other parts of the SP as the DP operations spread I don't know. I know younger engineers who come though UP's training and then come into the real world used to freak out when I started showing them the dreaded "fence". And, yes, I did have a couple even tell me they were told not to even use the fence and I told them that in my opinion that person was an idiot as the fence is very useful if you understand it. Whatever, it's not my problem what others do now because I am out of it - and happy. I do find it interesting that now the railroads that wanted "synchronous only" a few years ago are often coming up with special instructions telling crews to use the fence due to train separations - go figure!!!

 



Edited 3 time(s). Last edit at 08/14/20 19:11 by Railbaron.

When I was firing, I had a 6000 series GE. There is only one fence. With the old computers, there was always a delay. Coming into a Form B with a newer conductor and off of a hill top I was trying to move the fence and get setup down hill and to slow down for one of those “standby” foreman.

In pressing buttons trying to move it to the correct DP consit (one of our experimental three sets of power) somehow a second fence popped up.

Now the head end, mid train and rear engines were all doing something different.

I went “ahhhh!”

Engineer said “what?”

I pointed.

He said “aaaaahhhhhh!”

That was fun.



Edited 1 time(s). Last edit at 08/15/20 01:37 by MP683.