Western Railroad Discussion > Monster Manifest ~ UP Nampa Sub

Yesterday afternoon was unexpectedly busy around the UP Nampa, Idaho yard.
I caught several EB and WB manifests, including this one as it pulled WB out of the Nampa Yard.
Standing trackside, it quickly became apparent that this was a very long train.
As the train made its way westward, DSP 3 asked the crew if it was indeed 9,200 feet long and the crew confirmed it.
The power was 3X1 with the DPU placed closer to the rear of the train.
I've noticed more long manifests on the Nampa Sub lately, and many have a DPU placed farther back with no rear DPU.
What's the rationale for that DPU placement?

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If you tried to put the DPU on the rear of a train that long, the radio signals would be too weak at that distance.  I've heard that 8000 feet is about the max distance between power sets.  I'm sure this also depends on terrain and other conditions.

Brian Black
Castle Rock, CO

Thanks for the info, Brian.
I had never considered that, but it makes sense.
Phil Hoover



Edited 1 time(s). Last edit at 11/23/15 09:28 by philhoov.

This thread brings a question to mind. With all  I have heard and readabout DPU operation, I have not seen anything mentioned. When there are more than one set of dupes, do the B, C, etc sets relay the telemetry signals back to subsequent sets? When UP and BNSF have run long stack trains (18/19,000ft long) it would seem necessary. I suspect this is the case, but would like it confirmed. Also, how would this be affected when putting up a fence to run rear dupes independently? Thanks in advance.

I hadn't realized that BNSF or UP had run trains as long as 18,000 or 19,000 feet.
I thought UP didn't run trains with more than eight engines.
If so, how would they run trains that long with eight engines?
Phil Hoover

It is probably because of weight and loads and empties issues. BNSF runs ten thousand footers out of the LA basin all the time with front and rear units.
JB

A few years ago UP ran a 3.5 miles long train from Mesquite Tx (Dallas) to California.  That is 18,480 ft with 4 sets of engines.  I believe the number of engines was 10 or 11 with them being split into 4 different places.  Corrections welcome on the number of engines.

Just as is the case with manned helpers, it often is not a good idea to place units where they are pushing a long string of empty cars.  In the photo, it appears that most of the cars behind the DP unit are empty, so that is likely why the DP unit was not placed at the back of the train.

As I recall, most (maybe all) of the cars behind the DPU were empties.
Most of them were empty lumber cars.
Makes sense.
Phil Hoover

Doesn't UP still require the DPU nearest the head end
to be within 8500 ft of it?

philhoov Wrote:
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> I hadn't realized that BNSF or UP had run trains
> as long as 18,000 or 19,000 feet.
> I thought UP didn't run trains with more than
> eight engines.
> If so, how would they run trains that long with
> eight engines?
> Phil Hoover
The best examples are grain and ash trains that run here. What you'll see most of the time is 2-3 units up front, 4-5 in the middle, and 1-2 shovers. For monster trains it is the same. There are different terms for Mid-train units for monster trains. In CP, I've heard them referred to often as Mid-train remote/repeater, because usually the mid train unit repeats the signal sent by the head-end to the rear-shover. CP uses this method widely in their system, and I'm noticing it becoming more common on the UP system as well. Lately, I've spotted some oversized MNPPT trains that have a mid-train unit, then a rear shover, meaning that the mid-train unit is the repeater. Your train looks like a big MNPHK, which once exceeding the 8,000ft mark, regularly run with a mid-train unit. Something else that mid-train units are good for is they can use them for dynamic braking. You'll notice that trains with just a rear shover rarely use them for dynamic braking. Here's what they can do: Let's say that you have a two grades, the head of the train crest the grade, and the begins a descent, but it's a huge train, like a 12,000ft MNPHK, the head end is going to have to manage the part of the train that is going to push them down the hill. They can control each unit individually, so the head end can actually be in dynamic going down-grade, and they can throttle the mid-train just enough to keep speed for the other side going up grade.It's a much more efficient way of managing speed in the mountain districts

There has been a bit of discussion on the Canadian board about the issue of DPU placement ...

http://www.trainorders.com/discussion/read.php?15,3893677

CN now appears to be putting the DPU about a third of the way back in the train. Part way down the above discussion a hogger (Hoggerdoug) makes some interesting points about it.

 

Will MacKenzie
Dundas, ON

Plenty of 10-12K double stack trains operating on the BNSF in and out of Southern California (through Cajon Pass) with power on both ends. Excessive distance doesn't seem to be an issue down here.

Mr. MRL

     WW is probably more correct than the other answers. Just look at the situation and give a bit of thought to what the tractive effort is of one of these units. Now do you really want to shove on the empty cars . . . . through switches . . . . . . into and out of sidings . . . even on curves ?

I'm still confused about the number of engines UP allows on one train.
Someone commented on one of my earlier posts that it was a maximum of eight engines?

timz Wrote:
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> Doesn't UP still require the DPU nearest the head end to be within 8500 ft of it?

8500 feet behind head end consist to head end of DP remote consist

philhoov Wrote:
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> I'm still confused about the number of engines UP allows on one train.
> Someone commented on one of my earlier posts that it was a maximum of eight engines?

The rule is no more than eight locomotives on the head end of a freight train. Train management may authorize up to ten locomotives. These requirements include all working, isolated, dead in consist, and dead in train locomotives that are immediately behind the locomotive consist.

Light power moves may have up to 25 locomotives.

To add more to the placement on the UP. For the train pictures since it only has a single unit, less than 24 epa, the following applies,

The helper must be located within the rear 50 percent of the trains trailing tonnage, comply with restricted car requirements and hazardous material placement requirements and must be within 8500 feet of the head consist. 

tomstp Wrote:
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> A few years ago UP ran a 3.5 miles long train from
> Mesquite Tx (Dallas) to California.  That is
> 18,480 ft with 4 sets of engines.  I believe the
> number of engines was 10 or 11 with them being
> split into 4 different places.  Corrections
> welcome on the number of engines.

it was 9, three on the front two on the rear and two pair mid train.

Isn't the fact that coupler slack (broken knuckle) also pays a part in the location of where a DPU is placed in the train. I realize that one of the reasons for DPU's are to keep pressure on the consist (either pushing or dynamic braking) but I am sure the problem of pulling a coupler knuckle must also be a consideration.

Happy Thanksgiving to all.

Jim
Hatboro, PA​