I’ve seen several long freights that UP has put two engines in about the middle, with still a pusher or two at the end. Also, just saw a white reefer train and the cars were REALLY LONG!
You would think that a railroad with such a fine steam program would know better than to wear white (on their reefers). This will complicate testing of the Big Boy! You’ve got to hand it to UP though…they’ve been very persistent in their “bigger is better” theories over the years.
I’ve seen a lot of white Tropicana reefers that come out of Ft Peirce FL. They’re pretty long. And a Lot of orange ones too.
You see a lot more helpers in the middle out in California working either Tehachapi or Cajon Pass. I’ve seen 3 or 4 in front, 2 in the middle and 3 more on the rear.
Only once I saw a very long BNSF coal train that ran as your describing. It had two up front, two in the middle, and two at the rear. Definitely not a normal configuration for BNSF in the area.
When we took our trip to the Southwest a few years ago, we saw many container trains with 4 on the front, two in the middle, and two pushing.
Some times those long unit trains split up half way through the trip and doubling the helpers sends the required power along.
Of course everything I mentioned should be preceded with: If I remember correctly…
John
4 up front, 2 in the middle and 2 or 3 pushing is usual over Cajon Pass for long container trains, but the ones in the middle are usually just for the push over the pass; on the other side they are usually cut out. Then it’s back to 4 in front and either 1 or 2 in back, depending on the length of the train
The midwestern and western RR’s have been doing this for a while. They use the pushers/pullers in the middle for numerous reasons. Coupler strain reduction is one of the main reasons and there are several others however I forget exactly why. I think better mileage but mainly like I said reduced stress all around. NS has been experimenting with this on the Horseshoe curve and over the Allegheny’s as well.
I just have to wonder how pusher crews, weather in the middle or the back end, control their speed so they don’t bunch up the train too much, or end up being an anchor for the train.
Maynard
Look up NS pusher service over the curve and before that and before that and before that(with steam) …it’s old school art this country still has!
EDIT: counting Conrail and PC as one …if not it would be considered another “before that”
David Russell said:
The midwestern and western RR’s have been doing this for a while. They use the pushers/pullers in the middle for numerous reasons. Coupler strain reduction is one of the main reasons and there are several others however I forget exactly why. I think better mileage but mainly like I said reduced stress all around. NS has been experimenting with this on the Horseshoe curve and over the Allegheny’s as well.
Would coupler strain be an issue on relatively flat runs. From the coal fields of eastern Montana to Spokane is a relatively flat run, but the one time I witnessed it the train was very long, at least a mile plus on my odometer. I could see the need for that very reason. But I have also witnessed coal trains that long other times with 5 up front and 2 in the back with nothing in the middle. Experiment maybe? I also don’t see them breaking the train as the coal is a straight shot to China.
Davd,
In this day and age wouldn’t train control be all automated between trains up front/middle/ and end via radio or direct wired telemetry? I never have given any thought to it. I assumed it was all controlled from up front via computer.
You can have two types of power; manned units and DPU. The manned units are fairly rare and are reserved for specific helper districts (ie, Rocky Mountain passes). DPU or Distributed Power Units are controlled by the head locomotive via a system of radio signals. A backup system of using the air is also available in cases where the radio signal cuts out for a long period of time. Running a DPU train isn’t that much different than a regular train. The train will speed up, slow down, and set and recover air much fast with DPU than the same train with no DPU. A majority of the time the DPU is set up to mirror the exact throttle positions/changes as the lead locomotives, but you can ‘set up the fence’ which allows you to control the DPU separately from the head end. This makes the running a bit more complicated, but necessary (when cresting grades head end in dynos, rear in pushing for example, making a set out with the DPU stopped, etc). The DPU can be set up in a bunch of different manners, and if I remember the set up correctly you can have up to 3 sets of DPU in one train for a total of 4 different sets of power (head end, DPU 1, DPU2, DPU3). Each DPU ‘set’ can have an unlimited number of loco’s as the DPU radio is only ‘talking’ to the one locomotive that is linked. The rest of the locomotives are wired just like any regular consist.
One of the funny things I remember about DPU trains as when we would set out a grain train, and run the loco’s back to the barn light. We would grab the DPU’s from the rear of the train and only hook up the trainline. I would either isolate the DPU units, or have them mirrored with the head end. Some engineers would insist that you make all the MU connections and unlink the DPU, but it was mostly a waste of time because you had just finished running them as a DPU train, and simply gotten rid of the 110+ cars inbetween each set of power…
Any more questions? (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-undecided.gif)
Craig Townsend said:
Any more questions? (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-undecided.gif)
Umm. . . just one. Can I have a bathroom pass?(http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)
Devon Sinsley said:
Craig Townsend said:
Any more questions? (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-undecided.gif)
Umm. . . just one. Can I have a bathroom pass?(http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)
Ummm… NO! See GCOR Rule 1.11.1 for more details. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-undecided.gif)