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Thread: How does a freight train work.....

  1. #1
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    Question How does a freight train work.....

    I was poddling about a few minutes ago with a freight train on trainz and it occurred to me that I don't know how these things actually operate.

    Say you're running a freight operation. I'm assuming that some shunters will pre-assemble the rake for the loco to take on its journey at the starting yard. The loco picks them up and off it goes....

    Now, say its on a multiple drop run. How is it managed. Are the wagons for the first drop on the front or back of the rake? Does the train drop off wagons from the back of the consist at each drop and leave them for the local shunters to deal with once they've been dropped off (if so wouldn't the caboose get in the way?) Or does it decouple the front few wagons from the main rake, take them past the points and back them into a siding itself and then return to what's left of its original rake, couple up and head off to the next destination.


    I've never seen a freight yard at work and just realised while playing that I didn't have the slightest clue how this stuff happens in the real world.

    Anyone care to enlighten me please?

    Last edited by gazwald; August 21st, 2007 at 12:49 PM. Reason: spelling

  2. #2
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    im not for sure but i belive sd's or gp's or switchers run them to where they need to go.
    Please Visit My Blog Here!

  3. #3
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    also they rarly have cabboses anymore.
    Please Visit My Blog Here!

  4. #4

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    shunting is a very long task, depending on what has to go where, how much needs to be moved, if other wagons are in the way, do the wagons need loading/unloading? etc...
    first, the train would be put together by a shunter, each wagon would be put in order it would be dropped off, back to the front, considering wagons that might be added to the train and the layout of each drop-off point.
    the loco would be added to the front and the brake van/caboose is added to the back
    the train would then drive to the next drop off point, and the brake van would be taken off, the required waghons would be taken off and wagons would be added if need be, the brake van is but back on the end and the train goes to the next point.
    this time the caboose and the added wagons would all come off together (unless the wagons were required at this point) then all required wagons wagons would be taken off and new ones on, brake van and wagons are reattached and the train heads off to the final destination, the loco leaves all the wagons in a siding ready for shunters to take to their correct bays.
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  5. #5
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    Default

    Thanks guys,

    So as a general rule the loco actually hauling the main train wouldn't take part in the actual shunting, i.e. it wouldn't back its rake into a siding itself and leave part there.

    Instead a shunt at the destination depot would peel off the wagons that were intended for that location and possibly add additional ones to go on the rest of the journey.

    Have I got that right?

  6. #6
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    Default RE: How do freight trains work....

    The way freight trains are operated may be different in different parts of the world. They are certainly different by what the train is handling. My answer is informed by contemporary practices in the U.S.

    The simplest type of freight train operation is the "unit train". Technically, this term in the U.S. is used for trains carrying a single commodity from a single shipping point to a single destination. Examples of these types of trains are coal trains used to transport coal from a mine to a power plant, and grain trains, usually complete trains of covered hoppers loaded with any of a number of types of grain, from a terminal elevator, often to a port. Though they are not technically unit trains as such, there are other trains which are similar, in that they originate at one point, and are operated intact to another. Intermodal trains (trains carrying exclusively trailers and/or containters on flat cars) are pretty much unit trains. Except for the occasional need to switch out a bad-order (defective) freight car, unit trains do no intermediate switching; locomotives are coupled to the car at their origin point, and the train is handled as a unit to its final destination.\

    The other extreme is local freight operations. These might be in a small geographic area (such as an industrial park in the immediate vicinity of a switching yard), or they might be a local, working a significant portion of the right of way, serving on line industries. In these instances, the train crew is provided with a list of which rail cars go to which industries, and from which industries rail cars are to be collected. Before leaving the starting point, the conductor arranges the cars in the most efficient order for picking them up, and dropping them off; exactly where a car is in the train when it departs the origin point, will depend upon how the car can be handled with the least amount of switching moves. But other rules may come to play, too. In the U.S., there are regulations governing the placement of certain types of loads in the a train. Certain commodities may not be handled adjacent to the locomotive, and may not be handled adjacent to other types of commodities. An example of this is that a carload of a commodity defined as an oxidizer cannot be handled adjacent to a carload of a flammable material. Year ago, on the old Rock Island, a system wide rule required that a jumbo covered hopper car could not be coupled to a caboose, so that even unit grain trains always had another type of car between the last covered hopper and the caboose. Another Rock Island operating rule was that when a train was shoved across a highway grade crossing, if possible, the first car across the grade crossing had to be a caboose.

    Most other types of freight trains on the Rock Island were "blocked", meaning that cars going to the same place were located together in the train. There were published books, revised periodically, which specified for each train, in what order the cars were to be placed, and these were revised periodically. The order dictated was the order in which the cars could be handled most effectively. For example, one train left a terminal with a number of groups of cars (blocks); there were blocks for two intermediate terminals, and the balance went to the next major yard on the line. The block immediately behind the locomotive was set out at the first intermediate terminal the train came to; the block immediately ahead of the caboose went to the second intermediate terminal. When the train arrived at the first terminal there was neither yardmaster nor yard crew on duty, so the train set out the block from the head end in the yard on a track which was always left empty to receive the block. If there were cars to be picked up by this train, they were always left on the adjacent track, so they were added to the consist directly behind the locomotive. When the train arrived at the second intermediate terminal, there was a yardmaster and yard crew on duty, and the yard crew tied on to the caboose, and pulled off the block just ahead of the caboose; dropping the cut on the track designated by the yardmaster. If there were cars of to be forwarded on this train, those going to a particular set of destinations were picked up by the yard crew and placed just ahead of the caboose, or depending upon where the final destination of the train, placed into the middle of the train. When the train arrived at the next major terminal, it was in order so that all of the cars behind the the road locomotives to a certain point were going to the same destination. These cars were pulled away from the balance of the train, and cars from the terminal going to the same destination were added by a switch engine which shoved them to the rear of the first block, and the train departed. The next groups of cars were pulled off the train for switching at the intermediate yard, and the cars in the yard with the same destination as the last part, just ahead of the caboose, were attached to the front, road locomotives were attached, and the train left.

    ns

  7. #7
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    Default How does a freight train work.....

    I've never seen a freight yard at work and just realised while playing that I didn't have the slightest clue how this stuff happens in the real world.

    Again, informed by relatively contemporary U.S. practice, yards can be generally categorized into one of two types: a local yard, which services a particular set of industries, the size and which is dictated by the number of industries served, and the volume of work to be done at each; and a division, or terminal yard, which organizes trains, and consists of a number of groups of tracks. Within the terminal yard, each group of tracks serves a particular function, an inbound yard, where arriving cars are received, a classification yard, where the cars are sorted as needed, an outbound yard, where trains are build up, &c. If there are industries in the immediate vicinity of the division yard, there may also be a separate local yard.

    It does occur to me that a more complete set of answers to your questions would be had by devising a series of routes and scenarios, perhaps specific to railroading in the various parts of the world.

    ns

  8. #8
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    Thanks mjolnir, That's exactly the sort of stuff I was interested in and I appreciate you taking the time for such a detailed answer.

    One of the reason's I'm interested in this is that I've just started building my own layouts and a better understanding of this subject will help me to make a more realistic/operable layout for the goods yards I include in my layouts.

    This is a link to a screenshot of a very small local goods yard in my first attempt at a layout. http://img524.imageshack.us/img524/388/screen003pz0.jpg

    It's not up to the standards of other stuff I see on these forums (some of which simply amaze me) but hopefully it isn't too bad as a first attempt. As you can see its just a simple trunk & branches tree setup which stems from my lack of understanding on the subject and would probably be completely unworkable in the real world.

    As for the scenarios, yes I agree that would be a good starting point. As I only have Trainz 1.3 at present though, my choices are pretty limited. Hopefully I'll be able to resolve that soon though.

    Once, again, thank you for a very informative post.

    Gaz.

  9. #9
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    Default Hump Yard

    For Trainz :Quote by Bob Weber "you need the humpyard kit from TPR. Try http://www.trainzproroutes.org/forum...pic.php?t=2782" Thanks to the TPR people- IIRC
    In a hump yard the consist is sent "over the hump" - a rise or hump in the track - as the car passes slowly over the crest it is decoupled - it rolls clear and can be scanned electro- optically (like a supermarket scanner) - the Humpyard operator (or his trusty computer) then assigns a "road" and the switches are set - the car can be "retarded " with flangebrakes to give separation to the rolling cars and to reduce "bumping" of the product when they "couple" at the head end of their outgoing road. The motive power can then attach to the consist and it is on its way

    hope this helps
    (You could always attempt Tafwebs Proteus Yard (IIRC)- which was a Trainz shunting puzzle "generator" - Loads of fun- ? is it still around?
    @Gaswald - layout looks good -

    Waz
    Last edited by wazzer; August 22nd, 2007 at 07:38 AM. Reason: spellchecker doesn't work on finger - brian connection

  10. #10
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    I've seen a freight train in action in my town. The sidings are on different sides of the train. The railroad puts a locomotive on each side of the train. When they get to the first industy they stop and decouple the train. The first half goes to Frito Lay on the hill to drop off corn and patatos. The other half goes to Staples and a plastic company. The first half then goes down the line to next town. Same with the second. I hope this helps in anyway.

  11. #11
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    Thanks Wazzer.

    I've just found Proteus yard 2 on Tafweb's site with a quick google, I'm just loading it now and gonna give it a try.

    hump yards sound a bit of a scary concept, though ingenious.

    Anyway, Proteus is calling me. Must go try it!.

    Gaz.

  12. #12
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    Al Krug seems to have a pretty good explanation here...

    http://www.alkrug.vcn.com/home.html

    about cutting part of a train out and putting it into a siding...

    regards

    Harry
    Owner of AD427 and six chat bans. Config file modifier/creator. Oh btw... I'm gay. Kuid No. 427

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    LVMan's explanation is good in principle, but in practice, the situation is far more complex. It is true that intermodal cars are usually not humped, but then the intermodal train is most often (these days in the US, anyway) handled in a dedicated facility, which may or may not be close to a railroad division or terminal yard. In Dallas/Ft Worth, TX, for example, the UP's main classification yard is in Fort Worth, the original intermodal yard, by contrast, is on the East side of Dallas, about 40 miles away, where there is much more convenient access to the expressway system, and the newer UP facility is located south of Dallas, and located immediately adjacent to Interstate 45.

    ns

  14. #14
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    Default Operatiosn Special Interst Group

    Here is a great website that deals with railoroad operations.
    Model Railroad Operations SIG

    Dap

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