Very Long Trains

Trains Magazine General Discussion
1

I know that a couple of months ago UP test ran a very long intermodal (18,000 ft I believe) on the sunset route.

Has anything come of that? Are any more tests planned in the future and have train lengths increased as a result?

2

I’ve seen nothing published indicating whether or not the UP has plans to increase train lengths as a result of that test run.

So far all of the trains on the Sunset Route are what would be considered ‘normal’ length. Certainly nothing approaching that experimental run.

3

Would you suspect that UP would only want to dispatch 2 opposite direction trains to pass on a section of track that had maybe 50 miles of double track? That way precise timing (even 50 miles would only give a 25 minute window) of a meet would not be as much of a worry? Maybwe they will wait for much more double track to be installed? Maybe BNSF is waiting for same thing ?

4

Well why not just have the super-long trains uni-directional? Let’s say the standard on a line are 11,000 ft trains because you have 12,000 ft sidings. So run your eastbounds like normal, and park them in the sidings. Then you can have an 18,000 ft westbound just roll through, and the siding length is not an issue. You’d just have to coordinate it so that the shorter trains would have to be the ones that always went in the hole.

5

I’m recalling that the primary purpose of that train wasn’t about the length in and of itself-rather to test some new DPU software from GE. I believe every loco on that train was a GEVO. Oops…excuse me UP fans. That would be C45ACCTE.

6

The one direction ‘over length’ train method of operations is used on many territories with shorter than desired sidings… The problems come when the preponderance of traffic opposes the over length train and it must take siding the only place(s) it fits to wait for the parade of opposing trains. As long as traffic is relatively light on these kinds of sub-divisions such a operation can work…if the traffic level begins approaching the maximum capacity of the sub, it chokes the fluidity out of the operation.

7

Unfortunately sidings are not placed at equal time spacings (not distance). The other problem is the immediate unbalance of crews. There would be dead heading of many crews from the long train crew change points to their point of origin. HOS rules now would cause them to maybe be paid a full days’ pay just to D/H.

A point that has not been asked or touched on is how did GE get the signal to the secound and third DPUs. Did each DPU loco in the consist relay the engineer’s command to the next DPU?? Someone start a thread on this question when they have information? .

8

[:)]

One aspect of my railfan hobby is railroad telemetry and control signals - things like End-of-Train devices, Head-of-Train devices, and Distributed Power Unit (DPU) controls. When a DPU unit receives a command signal from the head end, it duplicates the command and re-transmits it as a “repeat” just before it transmits its own “status/response” signal. There is a bit in the signal structure that indicates that this transmission is a repeat, so another DPU will be able to differentiate an “original” command signal from a “repeat.” In addition, each command signal has a sequence number encoded in it to uniquely identify it. The DPUs carry this sequence number over into the repeat signals and the status/response signals. The head end DPU controller uses this sequence number to verify that a received status/response signal goes with a particular command signal that it has sent out.

So, if a long train has, say, two DPUs, one in the middle and one at the rear end of the train, the DPU in the middle of the train will send a repeat command signal that will be plenty strong enough for the DPU at the rear to receive clearly.

I suspect that there can be up to three separate DPUs in a string (long train), but I haven’t been able to verify that yet.

I think the power level of DPU signals is about 30 watts; I usually receive them reliably up to ten miles away.

[:)] [:)]

9

Thanks for that info and those insights, cordon - very interesting, and far more informative than anything on GE’s webpage for Locotrol -

http://www.getransportation.com/rail/rail-products/locomotives/on-board-systems/l.html -

and

http://www.getransportation.com/resources/doc_download/20-locotrol-brochure.html

or anything that I’ve seen anyplace else.

  • Paul North.
10

There can be up to four distributed power consists, plus the controlling lead consist.

Jeff

11

Cordon: I second PDN’s appreciation. Thanks very much and keep us informed of any changes, upgrades, etc

12

[:)]

General Electric has updated their web site considerably. There is a lot more information there than before, but no real technical “meat.” I e-mailed them asking for technical information, but they gave me only a courtesy reply. I’m not surprised; they probably don’t want to encourage people like me receiving and decoding their transmissions, which is what I’m doing.

It appears to me that General electric has done a fine job of evolving a simple, robust, and reliable approach to Locotrol. I hope they get to be a main player in the development of Positive Train Control (PTC) because I think at the present time PTC may be headed in the direction of being overly complicated, which may be one of the reasons the cost estimates for it are so high and many of the editorial comments (re: Fred Frailey of Trains Magazine) are so negative and discouraging.

In the last two months a new signal has appeared on the air here. I have no idea what it may be doing because I haven’t had an opportunity to analyze it yet (I use Roxio Sound Editor for that).

[:)] [:)]