Idea for a working "hump yard."

Discussion in 'Track Planning' started by Russ Bellinis, Aug 7, 2003.

  1. Russ Bellinis

    Russ Bellinis Active Member

    I was at the U.P. industry yard today to work on a Tropicana reefer. The car I had to work on was in the center track of a small yard ladder. I had to wait for the switch crew to finish switching before I could "blue flag" the track and work on the car.
    The ladder had a small hump in the yard lead. The crews would line the switches and "kick" off a couple of cars at a time. The cars, most loaded, slowly rolled down the slight grade to their waiting tracks. I doubt they ever got going more than two or three miles per hour. It would seem to me, that doing something similar on a model yard using cars with free rolling trucks like Kato, or Atlas would work pretty slick. I was thinking that if it was a double ended ladder with a small grade at each end, the cars would end up in the middle.
  2. garyn

    garyn Member

    Hi Russ

    I would love something like a hump yard, it would be fun to operate, and VERY cool to watch.

    But I see the biggest problem of a hump yard is real esate, or the lack of it. As large as a yard is, a hump yard would be even larger. Only a "large" home or club layout would have enough space. In N scale it would be at least 15ft long, from lead to lead, and probably longer.

    There are other problems, most easily solved.
    - The grade and height of the hump and the exit end could be found thru simple experimentation, as they would depend on the length of the classification tracks and the rolling ability of the cars.
    - The other problem is the quality of the turnouts. w/o a loco to pull the cars, they have to get thru the turnouts on their own. Too many turnouts to get thru and the car may stall. And to make it easier would you use #6 vs #4 turnouts? The #6 would make the yard even longer. This will also affect the grade/height of the hump.
    - Then like you said the trucks and wheels. Low friction and should not bind or create other problems going thru the turnouts. And ALL wheels must be in gauge to work thru the turnouts w/o stalling.
    - Car weight. Heavier cars will have momentum to keep rolling, vs light cars which will slow down faster. May have to make a min weight rule.

    - Car weight and wheel friction to a degree can be compensated by making the hump steeper.
    - To test the cars, something I heard about, a test track with a hump grade. The car is release on the hump grade and MUST roll to a minimum distance on the flat section. Note that the number of turnouts the car has to get thru will affect this test, as each turnout will slow the car down a certain amount.

    While not an impossible task, it is something that would require more than a bit of work. However, it would be a unique feature and it would be a LOT more fun to operate and watch than a flat yard.

    Go for it...!!!

  3. Matthyro

    Matthyro Will always be re-membered

    A good friend of mine has been experimenting and building an N gauge hump yard. See more of Helge's Railroad
  4. jon-monon

    jon-monon Active Member

    How do you plan to stop the cars without them bumping each other? I don't think I can get an LPB brakeman to pay attention long enough to put on the brakes :D :D :D
  5. Blake

    Blake Member

    I don't want to rain on your parade, but.....

    There was a large club near me that had an operating hump yard. They slowed the cars with air that came out of small holes between the tracks. It stunk. The cars had to go so fast in order to make it into the clear that it wasn't funny. The air would abruptly stop the cars (or even send them backwards on occasion). They fooled around with it for years. They had high standards for rolling equipment and all that but it made no difference. They tried to have one of the rails move back and forth to try to improve it. but it didn't help. Finally, they gave up on it. Northwest Shortline has a car that has some sort of flywheel inside that makes the car roll for quite a distance. They unfortunatly only have them in HO. I have not tried one of these but they aren't too expensive.
  6. Russ Bellinis

    Russ Bellinis Active Member

    At the U.P. yard I was at, the cars kept rolling until they either lost momentum, or bumped into and coupled to another car. The grade was so small that I doubt that any of the cars exceeded 5 mph. This particular yard could be easily modeled on a model layout without taking a lot of real estate. It only has about 7 tracks. There are a lot of other tracks in the Industry Yard, but the ones fed by this little hill is only 7 tracks or so. It would probably be very difficult to replicate a true hump yard operation on a model railroad because you would need a switcher to maintain a steady slow speed, and then uncouple cars "on the fly." The way this hill was used was the car or two that were going to be classified together would be pushed to the top of the hill, and then the train would stop, and the brakeman would cut them loose and let them roll.
  7. jon-monon

    jon-monon Active Member

    It's a neat idea. Maybe it would work with thw idea of keeping them moving slowly from a small hill. How about some wiskers of field grass sticking up between the ties to help keep them moving slowly and make them stop. Fascinating to watch them do that in person.
  8. garyn

    garyn Member

    I can't think of anything to simulate the action of the retarders. Modeling has a few other problems over the real thing

    - retarder, this is a bit more complex, as the retarder also has to know how heavy the car is so it can slow it down the correct amount.
    - mass, the prototype has mass = momentum
    momentum takes it thru the turnouts
    models lack mass, have to compensate w weight or a steeper hump
    there is no way to compensate for model cars of different weight
    - as was said each car will roll differently, some better than others, some worse. And like mass we have no way of compensating for the different rolling characteristics of the cars
    - model ladder turnouts will slow the car down much more than protoype. This also means the rolling energy has to be higher for the classification tracks at the end of the ladder than in the beginning. Again something that we don't have a retarder to compensate for.

    I think, for a model, we will have to be content to have the cars impact into each other. The goal then is to not have them hit too hard, and to not damage the cars.
    Or be satisfied that they don't contact and couple. The switcher will have to first push the cars together, to get them all coupled, then pull the cars out.

    A singled ended hump yard is more difficult to design but could be made. You would have to have the yard ladder on the flat vs the grade, so the yard switcher could pull the cars out w/o fighting a grade. Ah a problem to work on.

  9. Russ Bellinis

    Russ Bellinis Active Member

    This little hump yard had retarders, but there was no evidence that they worked. They looked to be solid rust! The cars never exceeded 3 miles per hour. As I was walking along the track to put out my blue flags, I noticed that some cars had stopped rolling ten feet short of the next car in line. Any train leaving that yard would need to back up to make sure all cars were coupled before leaving.
  10. Greg Elems

    Greg Elems Member

    Hi Russ,

    Nice subject and idea you have brought up here. I have seen one in HO that work fairly well. Personally, I like the flat switching better. Another friend of mine had a nice little yard, about the size you described. I would use an engine that didn’t have a fly wheel. He had Kadee couplers and magnetic ramps. I would uncouple the cars over the ramps and then push them fast enough to roll a ways down the track. The non-fly-wheel engine would stop fast and allow the cars to roll into the yard tracks. It was very similar to how we used to switch in Stockton yard. I would like to try a flat switching yard on my layout.

    Flat switching, as it was called, required speed. We would start by gathering up a rail, which was really going into a yard track and couple up all the cars. Then we would pull out a cut, a predetermined number of cars from the whole track. The number of cars would depend on where and how many were going where. Some cuts could be as long as 50 cars. Most were in the 20 to 30 range. The foreman would decide, by looking at his list of cars, how many to switch. Once the cut was pulled out of the rail, he would give a kick sign. The engineer would run the throttle up to run 8 and make the engine go as fast as he could. The pin puller would be at the car that was to be let go of and lift the uncoupling lever. The cut of cars would get up to 10 miles an hour or so and the foreman would stop the move. The engineer would stop the cut as fast as he could. The car would roll free down the lead to the track listed on the list. The fieldman would line the switch for the lead and have the next car lined into a different rail. This would go along until the cut had been completely switched. The pin puller would then take the engine back into the rail and get another cut of cars. This would continue until the whole rail was switched out. Some times a 70 car train would take 70 minutes to switch, while other times it could be done in an hour, depending on the number of cars let go at a time. In Stockton, we had a slight hump on the lead, but we still needed to really kick the tar out of those cars. Stockton wasn’t a huge yard, but it did have 27 or so classification tracks. With a good crew, we could switch out 300 or more cars in a shift. Often we would switch out a rail and then gather up the cars and put them on a departure track. What we were doing then was blocking cars and putting them in order of the work. The cars to be set out first went into the rail first and so on till the last cars were put in for the destination of the train. The best engine I ever pulled pins on was a GP-9. Buy the time I became an engineer, the best engine was a GP35. We had one that really move fast and would drag a cut of cars to a stop fast. Those days are long gone now. We aren’t allowed to get on or off moving equipment. Stockton is now the realm of Remote Control Locomotives.

    Greg Elems
  11. garyn

    garyn Member


    Thanks for the description. It's one thing to read in a book, its quite another to hear from someone who really did it.

  12. Matthyro

    Matthyro Will always be re-membered

    Very interesting write up Greg. It's good to read about what the prototypes do.
  13. Greg Elems

    Greg Elems Member

    Thanks guys. One thing the real thing has over models is mass. Once the momentum was going, it takes a lot to stop a car, especially on a grade. I’m still switching, only in Sparks Nevada and our yard is on a 1% grade. Now, all we do is bunch up the slack and pull the pin. The car rolls slowly at first and then picks up speed. We don’t let them roll far and they roll to a joint. When we have an empty rail, we shove the first few cars in and tie hand brakes on them. Sometimes we have to go back and add more hand brakes. When it comes time to pull the rail, we have to knock the brakes off. We also use air and try to keep all the air hoses buckled. Switching is a lot slower here too. Even with all the brakes we have to tie and knock, we still can switch out a good number of cars.

    Greg Elems
  14. The biggest problem, IMHO with a Hump Yard on a model is the basic laws of physics:

    g=9.8m/s/s (or 32 ft/s/s). This is UNCHANGING. This means *ALL* gravity accelleration on a model is 48 (O), 87 (HO), 160 (N) times too fast!

    The friction and drag rules are similarly too large. So you go too fast in scale speed on the drop, and then slide to a stop too soon.
  15. jon-monon

    jon-monon Active Member

    I like Russ's idea of an imperfect hump yard with lacking retarders and sometimes the cars bump or fall short. perhaps a varying grade can get us through the turnouts, then we can slow them down with less grade and some field grass or fiber wiskers. Something to play with some day.
  16. Ralph

    Ralph's for fun!

    I think Jon has a great idea with the fiber wiskers. You could experiment to see how many you needed to make the cars roll to a stop in a convincing manner.
  17. Ray Marinaccio

    Ray Marinaccio Active Member

    Ready for this?
    How about using small jets of compressed air between the rails to move the cars along the hump yard and /or act as retarders. Control them electronicly with IR detectors along the tracks that detect position and speed of the cars.
  18. jon-monon

    jon-monon Active Member

    (idea taken from some gauger schmardter than he)

  19. As Blake said at the top of the thread, that's been tried:

  20. Ray Marinaccio

    Ray Marinaccio Active Member

    Never Give up.
    I think " We" can make this system work. It Would need computer control to regulate the air jets according to the speed of the cars. I'd like to talk to the people that were working on this idea.

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