Hi, I understand the basics of the yard hump and how the yard works. The hump lets cars roll individualy into their track/lane, while the yard master(?) works with the switches to move these cars into their designated track.
However, after watching Unstoppable, I was surfing the internet about train brakes and came across the fact that freight cars without air pressure, would have the brakes on, as a fail safe. If this IS true, then how do yards and yard humps work?
1. Also, when switching cars around the yard, air hoses are disconnected, right?
2. Are these yard humps still used today?
3. Did(past tense) all large yards use these or just a few?
Thanks, I realy want some answers
Charles
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Modeling the Santa Fe & Pennsylvania in HO
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If a car has to be moved, it shouldn't usually have brakes on. This is true whether it's being gravity switched (i.e., humped) or flat-switched. I can think of four major categories of activity, but there are many other variations and nuances:
1. In flat switching, a loco and cars have the air line charged. The angle cock is turned on the adjacent car, but left open on the car that is being dropped. This maintains air pressure on the cut that remains with the locomotive, but allows the brakes to apply on the dropped car as soon as the air line parts.
2. In flat switching, no air is used. Cars are placed by the loco and hand brakes applied to secure the car.
3. In old-time gravity (hump) switching, the brakes are released and air is not used. Each individual car is ridden to a stop by a yard switchman who applies the hand brake to bring the car to a stop.
4. In more modern hump switching, nobody rides the car, but the car is slowed by pneumatic retarders as it coasts into its designated track.
There used to be a lot of hump yards on the larger railroads, especially at major yards where whole trains were disassembled and assembled. There aren't quite so many now, but some large ones still exist and are quite active.
Tom
Trainman440freight cars without air pressure, would have the brakes on, as a fail safe
Mike
ACY1. In flat switching, a loco and cars have the air line charged. The angle cock is turned on the adjacent car, but left open on the car that is being dropped. This maintains air pressure on the cut that remains with the locomotive, but allows the brakes to apply on the dropped car as soon as the air line parts.
Not necessary..When I worked on the railroad and we was kicking cars there may not be any air the engine brakes and throttle was used.
Now if we was fixing to drop three cars out of our train we would leave the air contacted and bleed the air from the three cars being dropped we would then kick the cars and let them roll to a coupling or the rear brakeman would ride the cut and use the handbrake to stop them. Then he would set the handbrakes on another car and after getting off of the car we would walk back to the caboose. This took time because we had to climb down one car and climb the ladder of the next to set the brake on the second car. Some old line brakemen would use the roof walk to the next car and climb down from the top then step around to the end ladder and brake platform-you never ever place both feet on this platform.You left foot stayed on the end ladder,your right foot on the brake stand and your left hand held the corner grab iron on the roof while you use your right hand to set or release the brake or vise versa if the Brakewheel was on the right side of the car.This happens when a car gets turn on a wye.
Why set two brakes?
Two brakes was set in case another crew kicked cars into those already there..A hard coupling could cause the cars hit to roll if one hand brake was tied down.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
Right, Larry.
I was speaking in general terms about four typical scenarios. I didn't mean to imply that other approaches aren't appropriate in specific situations.
ACY Right, Larry. I was speaking in general terms about four typical scenarios. I didn't mean to imply that other approaches aren't appropriate in specific situations. Tom
We also had to be careful not to bottle the air-a guarantee suspension.
For those that may not know. Bottling the air was leaving a cut of standing cars with air in the line.It was preferable to leave the angle cock open on the end car so any air could escape.
You see if the cars was left with the brakes applied the air could leak off and the cars could go rolling away so,we would drain the air and set hand brakes-remember those three cars we kicked from our train and how we bleed the air off before kicking them(see my first reply)?
What about your train air? We could leave the air in the line of course but,we had to set 3 or more handbrakes-say our local had 14 cars we would set 5 hand brakes.
BTW.The same rules applied for freight cars with lowered brake wheels.You still climb up the side of the car and step around to the end ladder and place one foot on the crossover plate leaving the other foot on the end ladder,one hand holds the the grab iron that run across the end of the car while you use your other hand to set or release the brakes.
You could take the lazy man's way and step into the gauge to set or release the brake but,if caught by a safety man you would be taken out of service pending a disciplinary hearing.
Why risk life or limb for those few seconds you saved by taking a unnecessary risk?
Today they use a brake wheel hook/rod /club or whatever they call it and you stay on the ground completely out of the red zone while setting or releasing handbrakes.
BRAKIEToday they use a brake wheel hook/rod /club or whatever they call it
Back to the OPs questions, hump yards go back to pre-WW2, perhaps as far back as the 1920's. By the 1950's, most new yards being built were hump yards, and old yards often had humps added.
Hump yards are very much still in use (I drive past one every day to and from work), but there are fewer now than in the past, primarily due to mergers leading to fewer yards overall. Seems to me Classic Trains or Trains or somebody did an article not too long ago saying there had been like 400 U.S. hump yards, but now there were only 100 or less(?)
As noted, retarders are used to slow the progress of the cars. Keep in mind, due to their mass, cars don't need to be going very fast over the hump. I suspect a search on "hump yard" on YouTube would probably bring up quite a few clips of humps in action; I know several railroads have produced training or promotional films over the years showing how their humps worked.
Trainman440However, after watching Unstoppable, I was surfing the internet about train brakes and came across the fact that freight cars without air pressure, would have the brakes on, as a fail safe. If this IS true, then how do yards and yard humps work?
Yes sorta.
If the cars are connected to an air source (engine or air compressor) the brakes will be charged. If the air pressure in the train line drops suddenly the emergency brakes will be applied.
Since the brake system is not hermetically sealed, if the brake system is disconnected from the air source for an extended period (several hours) the air pressure can leak out of the system and there will no no air pressure to apply the brakes.
Yes sorta. When the cars are uncoupled the air hoses will become disconnected, but the air hoses are not disconnected outerwise. When a train or cut of cars stops in a yard to be switched, the carmen or switchmen will walk the cut and "bleed off" the brakes, pulling a lever to drain the air out of the brake system and release the brakes so the car will roll free. This is done wherever the cars are being switched/classified in a yard, in all types of yards.
When the yard finally assembles the outbound train/cut, a switchman or carman will walk the cut, and connect all the air hoses manually. They then will attach the cars to an air source, either engines or compressed air pipes in the departure tracks, charge the brake system and perform the required brake test.
Hump yards are the major production classification yards. The biggest one it the UP's N Platte Bailey Yard, which is 8 miles long, has two hump yards, an intermodal yard, a spare coal car yard, a diesel shop, RIP track and 3 engine servicing locations.
No. There are also large flat switching yards. Hump yards are more efficient and higher production generally and are favored by railroads for large production facilities.
Dave H. Painted side goes up. My website : wnbranch.com
BRAKIEFor those that may not know. Bottling the air was leaving a cut of standing cars with air in the line.It was preferable to leave the angle cock open on the end car so any air could escape.
Bottling the air is bad. The original idea was if you trapped the air pressure in the train line by closing the angle cocks at both ends it would speed up the time it took to charge the train line back full service.
The problem with it is that air is a fluid. It can flow back and forth. If the brakes are set and the angle cock is closed while the brake reduction is being made, the air in the brake pipe is still moving after tha angle cock is closed, all the air flowing towards the engine piles up against the closed angle cock and then reflects back down the brak pipe. If you drop a pebble in the middle of a bucket of water the ripples will travel outward to the pail and then be reflected back into the bucket. Same thing with air. The moving air reflects back down the train line.
The way brakes release is the valve senses a pressure differential between the brake pipe and the air in the reservoir. If the pressure in the train line is a few PSI more than the air reservoir is signals the brake valve to release the brakes. Unfortunately that "ripple" of air traveling back down the brake pipe can generate enough of a pressure rise to cause a car to think its the signal to release the brakes. Unfortunately an innovation in brake design compounds the problem. Modern brake systems are set up so that whenthe brakes are released the brake valvle will dump any available pressure in the car's system into the brake pipe to charge the brake pipe faster. In normal operation that's a good thing, the brakes are charged faster. With the air bottled, that means the car dumps its pressure into the brake pipe, adding pressure to ripple. That can cause the next car to release (which adds its air) which causes the next car to release, etc. End result is the brakes release on the entire cut/train.
As Brakie said that is a big no-no.
Dave,In safety class they said it was due to air leaking and slowly releasing the brakes and the cars could start rolling.That was in my Chessie classes in '78. Thanks for explaining it better.
I've been told by retired railroaders(CSX,CR,NS) bottling air today will get you fired.
wjstixBack to the OPs questions, hump yards go back to pre-WW2, perhaps as far back as the 1920's. By the 1950's, most new yards being built were hump yards, and old yards often had humps added.
Actually hump yards date back to the late 1800s. The cars was braked by men called hump riders-they rode the car and braked to a coupling. Several switch tenders would line the switches into the bowl tracks.
Needless to say many fell to their deaths from hard coupling or by losing their balance.The families of these men kept a clean white sheet in case the dreaded knock on the door came.
BRAKIE Dave,In safety class they said it was due to air leaking and slowly releasing the brakes and the cars could start rolling.That was in my Chessie classes in '78. Thanks for explaining it better.
You are absolutely correct that the air leaking off could be a problem too. That's more a problem with relying on the train brakes to hold a standing cut rather than setting handbrakes. Not setting handbrakes is another opportunity for spectacular failure (Lac Megantic).
BRAKIE Actually hump yards date back to the late 1800s. The cars was braked by men called hump riders-they rode the car and braked to a coupling.
In older railroad magazines you can find pictures of LARGE motor cars or tramways that were used to get the switchmen riding the brakes from the bowl back up to the hump. A hump might employ dozens of switchmen to ride the brakes. After they rode the car into the bowl they would have to walk out of the bowl (crossing live yard tracks) and then get carried back up to the top for the next car to be switched.
BRAKIE wjstix Back to the OPs questions, hump yards go back to pre-WW2, perhaps as far back as the 1920's. By the 1950's, most new yards being built were hump yards, and old yards often had humps added. Actually hump yards date back to the late 1800s. The cars was braked by men called hump riders-they rode the car and braked to a coupling. Several switch tenders would line the switches into the bowl tracks. Needless to say many fell to their deaths from hard coupling or by losing their balance.The families of these men kept a clean white sheet in case the dreaded knock on the door came.
wjstix Back to the OPs questions, hump yards go back to pre-WW2, perhaps as far back as the 1920's. By the 1950's, most new yards being built were hump yards, and old yards often had humps added.
Back in the 1980's K-Line put out a book on model railroading, about half of which was a reprint of a book from about 1940. It had some 'real' railroad pics, including one showing guys riding high up on the car's end ladder in a humpyard. Not much fun when it's cold and icy I'd think.
BTW...re to the original post, "Unstoppable" really isn't a true example of railroading (as has been noted in early posts about it) so I'd take anything from that movie with a grain (or chunk) of salt.
wjstixIt had some 'real' railroad pics, including one showing guys riding high up on the car's end ladder in a humpyard. Not much fun when it's cold and icy I'd think.
Another good read about the early years is "Bradford The Railroad Town".It covers PRR's yard operation at Bradford,Ohio before PRR closed it and moved the yard operation to Columbus.
Today all that remains in Bradford is a PRR cabin car..CR removed the tracks in '85. Last I had track the Railroad YMCA was still there.
Okay I think I get it now. Thanks for all the replies!