Lack of humping

[jimrice4449]

in response to Pojack's question, yes the bowl is(or should be) just what it sounds like. The one big mistake I made on mine (ar least the one big mistake that I wasn't able to correct )was to go from +4" at the crest of the hump to 0 el. at the lower end. I should have gone to -.5 or so just short of the lower end switches and then up to 0 el. through the lower end switches. As it is, if a car gets through the retarders or I'm dropping a car into a clear track it tends to get into the lower end switches.
In respnse to Ted's question, at the crest of the hump there are two KD magnets. When I was laying the thing out I ran some cars up the hump and observed at what point the slack went from bunched to stretched. Ufortunately the longer cars stretched at a point well short of the point shorter cars did, hence the need for two uncoupling magnets to stretch the distance of the point at which cars would uncouple. In operating, you can't do as the prototype does and keep shoving at a steady pace. When a car (or cut) uncouples you stop the engine, operate the retarder, then check the next car, line the switches and the retarders for that track and shove until the next car uncouples. I rigged my panel with a pushbutton and on/off toggle switch. As the cut is shoved up for the first move I adjust the speed and, as the first car starts down into the bowl, I throw the toggle switch stopping the engine. From then on I control the engine by pushing the normally off pushbutton. As cars are shucked the cut tends to move faster so I have to adjust the speed occasionally. An experienced operator can break down a fifty car train (in two halves) in about 15 minutes, which, suprise suprise!, happens to be the time it takes an experienced lower end operator to make one up (again, in two halves) I'd like to claim this is an example of my brilliant planning but it was just dumb luck.

[Anonymous]

jimrice4449, please pardon my "slo-mo" grasp of the momentum issue. Hypothetically, if you need to send a 4 car "cut" (e.g., tank cars) to a single track while the next (e.g., gondola) must go to a different track, followed by yet another 'cut' of 2 cars (e.g. reefers) to a third track...is the momentary contact switch for uncoupling "iffy?" Next question, would the same weight for every car help in selecting the retarders setting in advance? Heavy loads for flat cars for example, could bring them close to the same weight as the heaviest car "over the hump." These are just random questions on an absolutely fascinating aspect of the hobby. Regards.

[Anonymous]

Since all the pros and cons of using a hump yard in a layout have been discussed, all I have to pass on is some prototype info. There is a CN hump yard in Winnipeg, Manitoba. It's called Symington yard. See ya!

[jimrice4449]

First, the pushbutton is held down for as long as you want the engine to move. To stop it you just let go. This is to obviate the need to keep twisting the speed control knob. In my system cars are switched by car number. Rather than use a written switch list I use the train as its own switch list. For example east bound trains are lined up according to the final digit of the car number. The first 3-5 cars have numbers ending in 1, the next few 2 and the cars immediately ahead of the caboose end in 0. When that train goes over the hump the cars are routed according to the next to last digit in the car number. So, to take three cars as an example, ABC XXXX21 would go to track 2, XYZ XXXX91 to track 9, PQR XXX51 to five and so on. If you're not hopelessly confused yet this should do it. The exception to this reefers. When humping cars that arrive in the yard lined up by the next to lasr digit ALL reefers go to track 11. What this does is block reefers in eastbound trains on the head end (as would be prototypical to facilitate re-icing enroute) while scattering westbound reefers (returning empty for reloading) throughout the train... The practical advantage of this is providing an obvious indication to the hump crew of whether a train is eastbound or westbound and therefor which of the last two digits of the car number is to be used to route the car. This system also provides the lower end job with instructions. Typically a given track will have 3-5 cars with the last digit of the car number corresponding to the track number, then a few next to last and then more last. What the lower end job does is pull the last numbers, make a cut, and double over to the next rack and repeat until he has the train made up.
The wieght of the car is irrelevant to the retarders. I wieght all of my cars by length starting at 3 1/2 oz for 40 ft. cars and adding 1/2 oz per inch. The retarders are controlled with a pushbutton for each bank (upper, middle, and lower, although I'm going to dispense with the lower). As a car arrives at the crest of the hump, the move is stopped and the operator notes the relevant digit of the car number. He then lines the switches for that track, then lines a rotory switch to activate the retarders on that track and starts the move until the car begins to roll on it's own. As it approaches each bank of retarders he gives a long blast, a short shot, or no air at all, depending on its speed and the number of cars already in that track.
I'm afraid this might be one of those things that sounds hopelessly complex when explained, but but actually works remarkably well without having to mess with any paper work, cards or what have you