PTB Precision Train Builder..

[Euclid]

The ultimate length of trains will be governed by the communication limits between distributed power consists.

What is that ultimate length? Is there any way to extend it by further technology development?

[MMLDelete]

Lithonia Operator

jeffhergert

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.

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

Thanks.

[SD60MAC9500]

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

Jeff don’t be surprised in the future if one day you get to your terminal and have a 22,000’ train waiting on you…

[MMLDelete]

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

Two questions:

• Why are bulk commodity trains able to have better radio connectivity between DP consists than other trains? (6000 ft. vs. 8500 ft.) I don’t get what you’re saying about two trains in one, since it would seem like distance is distance.

• What are the most significant additional challenges to an engineer as trains get longer? (I’m guessing the word “braking” will appear somewhere in your answer.)

I was looking at the video of that giant UP train linked in this thread. (Wow!) Each of the four power consists has two units. So four of those units are mid-train. It seems like if they really want to run longer trains, they could get around the radio-distance issue by having those four units run as singles, so they could be spread out, resulting in shorter distances beween engines. Now, building such a train would be a huge PIA, so maybe it wouldn’t be worth it.

[BaltACD]

PTB Fail

https://www.youtube.com/watch?v=K4bhpSqTfvo&feature=youtu.be

[jeffhergert]

The longer distance allowed bulk trains, loaded or empty, is because those trains are usually two separate trains that have been combined at one terminal into a single train. The two trains might be for two separate destinations. The longer distance between DPs means they don’t have to reposition or create a third DP consist for the combined train.

Down the (rail)road the train will be split back into the two separate trains for the final legs of their trips. Normally, the combined train assumes the symbol of the lead train. When the train is split up the second train assumes it’s original symbol. However, the location of the split becomes an intial terminal for the resumed symbol. It needs a full initial terminal air test and inspection.

There can be only 5 DP consists. The lead plus four remotes. If each of the remotes had two engines, you couldn’t break them down into single units working as 8 remotes.

The most challenging thing is keeping the train in one piece. Controlling buff and draft forces and slack conditions while the head part is going uphill, the middle going downhill and the rear again going uphill can become tricky. Especially so if the train has many cushioned drawbars.

Jeff

[MMLDelete]

Thanks, Jeff.

[SD60MAC9500]

For those looking for more info on PTB check it out here. They also have a short demo of the software available.

[BaltACD]

For those looking for more info on PTB check it out here. They also have a short demo of the software available.

Demo appears to be a ‘wiz-bang’ for techies that think they are railroaders. Gee - we can export various graphs and calculations of ‘trains you want to run’ as if Operations will pay attention to them in the first place and it supposes that those switching tracks that will make up the train have any knowledge of the options available in how to switch cars into the tracks that will ultimately make up the trains.