Classification Yard Operations

Discussion in 'Model Rail Operations' started by Tad, Mar 14, 2004.

  1. Tad

    Tad Member

    Posted with permission.

    These are a couple of posts made by Dennis Storzek on the Ops-Ind List concerning operation of a classification yard.

    >Quite the contrary..... you pull each track, looking for the cars on the
    >switch list (they are the cars that are supposed to be somewhere in the yard
    >that go into a train you have to make up)....
    >As you find a car on your list, you mark the track number next to the car
    >number. When the full cut from that track is clear of the turnout that
    >leads to the track you are building the train on, you start cutting the cars
    >you need...

    I hate to disagree with you, but I must. This is not the way a
    yard is worked, and the failure of so many people in this hobby to pick up
    on that fact has cause no end to both poorly designed yards, and poorly
    designed car forwarding systems. What you've described is commonly referred
    to as "cherry picking", and assumes there is no organization to any of the
    cars in the yard, and you randomly shuffle through them to find the ones
    you need. Yes, it is occasionally done this way in car storage yards, where
    most of the cars are going to stay, but it is not the way cars are classified.

    What you have described would be akin to a postal clerk sorting mail by
    grabbing a handful, picking out all the ones for your street, and throwing
    the rest back. He can then do it all over again for the next street. Yeah,
    it will eventually get them all sorted, but it is a slow and inefficient
    way to do it. In reality, the postal clerk has a pigeon hole for every
    destination he has to sort for, and when he grabs a handful of mail, he
    sorts each and every one in his hand. When his hand is empty, the job is done.

    The same goes for classifying cars in a yard. Part of the yard is devoted
    to tracks for arriving trains, the "arrival tracks", and the cars on these
    tracks are like the pile of mail in the pouch waiting to be sorted. Most of
    the tracks in the yard are used as "classification tracks"; these are the
    pigeon holes. Depending on the yard, they may be permanently assigned to
    certain destinations, or they may be assigned on an ad hoc basis, but once
    assigned, the assignment remains until that track is pulled to build an
    outbound train.

    When an arriving train is to be classified, the cars are listed, and each
    car is assigned to a track based on its destination. The cut is then
    pulled, and every car is sorted; none are put back into the arrival track,
    so it is open to receive the next train.

    When a train is built, the tracks with the sorted cars are pulled in the
    order that the blocks are to be placed in the train, with little if any
    additional re-ordering. The only reason to switch cars when building the
    train is to provide proper "cover" for haz-mat cars. The train is then
    charged, either on yard air or with a locomotive, and the air tests made.
    There may possibly be additional switching to cut out cars that fail the
    brake test that the car men can't repair in place, but that's it.

    You can see from the above the shortcoming of many of the computer
    switchlist programs; you can't switch the yard from the consists of the
    trains to be built, you need a "cut list" for each train that has arrived.
    Of course with cards, the cards can be used as the cut list by simply
    working off the stack in order, disposing of each car in turn. However, it
    works even better to spread the cards out on a shelf, so that multiple cars
    to the same destination can be switched as a block; working off a stack of
    cards means the next card is always a mystery until the card before is
    filed. As the cars are switched, the cards are filed in the box for that
    track, and when the train is built from the blocks on the class tracks, it
    is simple to just pick the groups of cards out of the boxes in proper
    order, and the resulting pack becomes the "wheel report" for that train.

    What happens if there aren't as many tracks available as destinations? A
    typical problem that the prototype often solves by classifying two
    destinations to the same tack, then pulling that track and classifying it
    again to sort those cars into two blocks. This almost always happens on
    model layouts with the cars for the local, since this one train may need to
    be blocked for five or six separate destinations. This is typically handled
    by designating one class track for "shorts" and throwing all the cars for
    the local into it; when it is time to set the local this track is pulled
    and switched again into station order, using what track is available. If
    there isn't any track available, then the last resort is to cherry pick the
    cars; sorting out all the A's and throwing everything else down the ladder,
    then gathering them up and sorting out all the B's, etc. until the track is
    in station order. This is only the last resort, however, as with five or
    six blocks in one train, each block is going to be short, and there should
    be enough room on at least some of the class tracks to take a few more cars

    Dennis Storzek

    > >The only reason to switch cars when building
    > >the train is to provide proper "cover" for
    > >haz-mat cars.....
    >Not that simple....
    >Besides hazmats, trains and blocks get re-organized for (at least):
    > - long - short combinations
    > - heavy - light combinations
    > - max tons trailing, depending on various car types
    > - certain contents in open top cars
    > - shifting loads
    > - operating refrigerator units, and depending whether it is gas
    > or diesel
    >and a few dozen more issues....

    It seems we're had this discussion before. It would appear the position you
    take is, ...there are so many exceptions to the blocking rules that model
    railroaders can't possibly expect to keep them all straight, therefore they
    shouldn't even try, and just cherry-pick their yards....

    I disagree. First off, all of the issues above are car placement issues,
    not blocking issues. Blocking is dictated by where the cars are to be
    set-off; car placement is dictated by haz-mat and train dynamics, and
    trumps blocking, making more work at the setout point. It is still applied
    only to the sub set of cars that are going to be made into THIS PARTICULAR
    TRAIN, not to all the cars in the yard, so one still sorts the yard by
    destination first. To work your suggested "five track yard", I'd still need
    a cut list for each arriving train, so I could classify into tracks by
    destination. To borrow from Roger's example:

    East Local trk1
    West Local trk 2
    Location Proper trk3 (to be delivered by the yard switcher
    Westbound trk4
    Eastbound trk 5

    An arriving train or set-out block would be classified to tracks 1,2, and
    3; a returning local freight would have its consist classified between
    tracks 4 and 5, but they would all be classified first by destination. The
    fact that they would later need to be re-ordered again is immaterial, the
    point is that the prototype classifies first by destination so all the cars
    for a given train are on one track, or group of tracks, and they don't have
    to run willy-nilly all over the yard looking for cars to build the train.

    As to the issue of what software I had in mind, none. I have not had the
    opportunity to operate on layouts using any of the various packages, so I
    can't comment. I'm only pointing out that if one is trying to operate
    photographically, and adopts a software package that doesn't provide the
    tools to do so, one is going to have nothing but frustration. Therefore,
    people first need to understand how a prototype yard is typically worked,
    then look for the features in the software that would either help, or on
    the other hand prevent, them from doing so. Then they can make an informed
    decision on car forwarding software.

    Dennis Storzek
    Big Rock, IL
  2. Tileguy

    Tileguy Member

    I think Dennis covered that topic exceptionally well, thanks Tad for bringing that one on over and thanks Dennis for allowing it to be shared with the gauge members.

    I would add one thing about classification and this has to do with the handling of Iron ore.

    Iron ore is graded and classified according to type.The reason for this is believe it or not,the ability of creating recipe's of ore preloaded and ready for the mill.When the mill calls for an order and designates the boat,it also designates how they want the ore loaded and specifies certain recipes to be loaded into individual holds.The switchlist is created based on this information.It streamlines the manufacturing end of the operation tremendously.the yardmaster than makes up his trains accordingly.of course ore is also classified in piles in storage area's near the ore docks and belted to the chutes(but thats another story);)
  3. spitfire

    spitfire Active Member

    I am planning a classification yard, so this is very timely advice!! Thanks for posting it Tad.


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