Computer algorithms can and do result in unintended consequences. Besides, computers don’t accept blame and can’t be disciplined.
This PTB program was not developed by an outside vendor, but rather by the U.P. itself by hiring an independent consultant who used to work as a dispatcher for them. The railroad will create the train list of cars, and then run that through the simulator. The article says this:
“PTB allows you to create a train you want to run, then run it virtually across a territory in a fraction of the time needed,” Grudle said. “It can simulate a 300-mile train run in about eight minutes.”
When it says it runs the train virtually in a fraction of the time needed, apparently that means to create and run the simulation in a fraction of the time needed. It sounds like they mean there is less “time needed” for running the program compared to the old way of not using the program.
What is that “old way” other than just some basic decisions about following the existing company rules regarding where to place empties and loads, and other key points about car location in a train?
I guess it means run the simulation in a fraction of the time needed to run the train.
It would be very interesting to creat hypothetical trains of extreme length and power, and run those over the territory to see what happens. Try trains of 1,000 cars or more for instance.
Not necessarily. All you would have to do is input your actual previous or current real world train data; schedule, crew changes, track speed, avg. speed, operating profile, length, weight, HP/ton ratio, or maximizing trailing tonnage to your consist (DPU’s included). The algorithm will try to give you the best possible outcome.
Though as Jeff stated previously what happens if cars are bad ordered? Get a knuckle? Unit fails enroute? Bad weather as stated by MC…
Though I will say let’s see how
I would say that’s the reason UP had this software developed. To see what the hypotheical’s are to run even bigger trains, and what any pratical limits would be… If the software shows you can successfully run a 20,000’ stack train. I wouldn’t put it past UP to trial and even put into regular operation a train of such proportion. Will it be a mess? Possibly… Remember that 3 mile long stack train UP ran back in 2010? That was just the beginning.
https://www.latimes.com/archives/la-xpm-2010-jan-13-la-me-monster-train13-2010jan13-story.html
“PTB allows you to create a train you want to run, then run it virtually across a territory in a fraction of the time needed,” Grudle said. “It can simulate a 300-mile train run in about eight minutes.”
As in any simulation, the proof in the pudding is whether the simulation has been validated. Having the simulation developed by a former dispatcher helps, though I would wonder if it takes all of the relevant train dynamics into consideration, e.g. slack run-in.
FWIW, simulating slack run-in has been something I’ve wondered about since reading “9800 tons” article in a late 1970’s Trains. Article was written be a former GM&O engineer about handling a train at least a third heavier than what the dispatch told him. Considering all of the time scales involved in tracking every single car and accounting for the actions of free slack and draft gear, I would be astonished that it could be simulated in anything close to real time.
PTB is just something they want to validate their belief that they can keep on building and operating longer and longer trains. That a certain percentage of ever longer trains is of no consequence, as long as the acceptable failure rate is not exceeded.
Jeff
Jeff, I don’t understand your second sentence.
A failure in 1 in 100 trains may be acceptable - failure in 20 in 100 trains may not.
There is some level of failure that is acceptable in train operation (as hard as you may try you will never get to zero failures). Operations in these kinds of circumstance is really a exercise in probability.
Just to clarify, I mean to create the hypothetical (virtual) trains of extreme length and power, and then run those hypothetical trains as being hypothetical models, over the territory as being hypothetical. It would not actually be a real train, so there would be no risk. It would be a cheap experiment that might yield mind boggling results which might be used in various ways.
Even if the DPU transmission cannot be extended as far as desired, just model the train as though it has unlimited DPU transmission length. Just set that issue aside and see what the makeup program thinks of an super-long train.
Then run a simulated train of say 50,000 cars, and see if the program can arrange the train makeup so that it works without any problems. That would be quite the news story if the system says it works fine.
Try it with mixed consits and with unit trains. What do you think the system would say about a 50,000 car train? I suppose it might say something about grade crossings.
My bet is that the program does NOT have any grade crossings in it. Only the Rairoad. Public Relationsis a different department.
The next question is how long it will take to build that train.
Just to clarify, I mean to create the hypothetical (virtual) trains of extreme length and power, and then run those hypothetical trains as being hypothetical models, over the territory as being hypothetical. It would not actually be a real train, so there would be no risk. It would be a cheap experiment that might yield mind boggling results which might be used in various ways.
Even if the DPU transmission cannot be extended as far as desired, just model the train as though it has unlimited DPU transmission length. Just set that issue aside and see what the makeup program thinks of an super-long train.
Then run a simulated train of say 50,000 cars, and see if the program can arrange the train makeup so that it works without any problems. That would be quite the news story if the system says it works fine.
Try it with mixed consits and with unit trains. What do you think the system would say about a 50,000 car train? I suppose it might say something about grade crossings.
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I understood what you were inferring, but the thing is the territory is not going to be hypothetical and UP wouldn’t be running a 1,000 car train. At least one hopes…I’m sure the numbers will be run on hypothetical trains of extreme tonnage and length, but nothing of the sort in your comment. More than likely…300 cars, 400 cars, 500 cars? Would be the extreme hypothetical range. Though wouldn’t anything over average length and
Extreme (and in many cases not very extreme) trains are built in ‘doubling’ two or more tracks together to end up with the final over the road trains. When trains are ‘doubling’ their trains together, they BLOCK off access to that end of the yard by any other trains. Doubling takes TIME and 24 hours still is the limit of the day. If it takes a hour to double a train; there is a maximum of less than 24 trains per day at that location; if doubling takes 2 h
SD60MAC9500,
I am not suggesting running larger than normal trains on the simulator with the intention discovering the practical limit for the purpose of running then as actual trains at that limit. The PTB system would serve its purpose if train length had a pre-established maximum and the PTB would just arrange the train consist to run as safely as possible under that maximum. And that is probably the actual goal.
It is likely that railroads will test the limit with trains exceeding the current maximum. If 600 cars would be in that range, maybe they would build such a train, obtain the analysis of the PTB, and then run the actual train if the PTB says it can be done without problems.
However, in the background has been this ongoing quest to learn just how long a train can be without being overcome with a variety of mechanical malfunctions such as break-in-twos, string-lining, derailments, etc. Even if these maximum possible length trains are never actually put into commercial operation, it seems that the industry would like to know the answer to the practical limit to train length. It is just part of the premise of monster trains.
All I am saying is that as long as they have this PTB that can predict what happens with train dynamics, ask it to analyze a train that is really long just for curiosity sake. That is why suggested having PTB analyze a train of 50,000 cars. That looks like about a 475-mile-long train.
I am not suggesting that such a train should be physically run for even a test. I
UP has already run an absurdly long train as an experiment that has yet to be repeated.
CSX is currently running trains in the 13,000 foot range in Ohio.
One major problem with such long trains is that not all lines are capable of handling them.
As I have tried to explain, I am not suggesting running actual extra long trains. I do realise they have been run for test purposes, but have not been put into regular operation. There are real risks in testing record breaking train lengths in acuality. But there is no risk in doing it virually in the PTB program. So I suggest running a truly long train in the PTB program just for grins. So that is why I suggest running a virtual train that is 475 miles long. What do you think PTB would say about it? What do you think the unions would say about it?
I think it would find workable consists for trains much longer than what has been tested in actuality. But it would certainly be interesting to see what sort of problems it finds as it tests trains of increasing longer consists. It would show a reality that has long been speculated on, but never fully confirmed, especially after the advent of DPU.
I wonder if they will add ECP brakes to the PTB program and see what effect that has. That would be extremely interesting.
Back in the late 1960’s, N&W did run a 500-car coal train with 3 SD45’s up front and 3 more as mid-train remotes. N&W found that it could be done but it was hardly practical.
Sorry, I must’ve edited out the part that of a certain percentage of longer trains will have failures. I rewrote it a couple of times and missed that I took out some words.
Jeff
The ultimate length of trains will be governed by the communication limits between distributed power consists.
I’ve heard BNSF runs an intermodal in the neighborhood of 18000 ft on a regular basis. We have manifests that often reach 15000 ft. I know there was one manifest that was 17000 ft. 18000 ft is our limit with 6000 ft between DP consists, except bulk commodity trains can have 8500 ft between consists. That’s because the bulk trains are just two trains combined into one.
I’ve been in the right hand seat for 15 years. It’s not that long ago when many of us thought 9000 ft to 10000 ft trains were monsters. Now you’re happy to get one that short. The ones 13000 ft to 15000 ft are now the monster trains. The more you run the big ones, the more one gets used to them. I wonder if there will be a day when 15000 ft will be considered a short train.
Jeff
When I hired out in 1965 on the B&O St. Louis Division the ‘normal’ train size was 60 to 80 cars and about 3000-4000 feet in length. At the time ‘train length’ was not a particular feature in the dispatching of trains and it was not a figure that was reported when giving the train’s consist to the Train Dispatcher. A MONSTER train would be one of 100 cars and over 5000 feet in lenght.
Upon returning to Dispatching in 1990 on CSX’s Tampa Division I got critized by the Division Superintendent for authorizing a train to operate with ONLY 160 cars - he wanted 180 cars MINIMUM. As I later learned that train normally operated with 200-220 cars and 9000 feet (feet was a required data point of a train’s consist). During my years with CSX 5000-6000 foot trains were considered ‘baby trains’, but Conductors still had two miles or mor