Western Railroad Discussion > How are bottom-dump doors opened?

I know that bottom-dump truck trailers are hydraulically powered. How do they do it on bottom-dump railroad cars? The only source of power is the air brakes line; do they tap into that? If so, what does it look like to the head end (or does the power automatically maintain pressure)?

you mean they arent opened by electro-magnets under the track?

Rapid discharge bottom-dump cars are opened pneumatically using a separate air line. I do not know how the separate air line is charged.

Actually, all the bottom dump trucks I ever drove were pneumatically operated from a separate tank on each trailer that was refilled by the regular brake system air compresser.

Regular bottom dump ballast cars have handles, dogs and cranks that open and close the hopper doors. There are ones on each side and ones in the middle. To spread ballast, you push or pull the cars at walking speed and the MofW personal open them as they need to. Sometimes they will put down a new tie to help spread it down to the rail height. They just put it in front of a set of wheels and it slides right along. After your done, you give em a bang with the engine to get all the loose stuff out and the roll the doors up.

On the big side dumps, they are charged from the main resevior on the engine. Ive had brakeman try to use the trainline but it sets the brakes and there isn't enough air. With the main resevior you have 130-140 lbs. There is a rod on one end to dump it one way and a rod on the other for the other way.

Nudge

Main Reservoir air is used, same with Side Dump, "Difco" cars. If the dump system used brake pipe air: (1) there is not enough pressure, (2) it would interefere with the operations of the air brakes. For example, lets say you have a 90 lb train line. You're on a steep grade and going to dump ballast or side dump rock. You would want to use your air brakes so lets use a 12 pound reduction. Now your brake pipe is only 78 lbs, but could be lower on the rear do to leakage. Now you try and dump the load, the air drops, demanding more from the brake pipe. The air brakes set even more because of the demand. When the attempted dump is done, the air builds back up, then the air brakes release and the train rolls down the hill.

The Herzog ballast train uses a hydraulic means to open and close the doors. Between the cars is an electric cable to provide power throughout the train.

YM

Altho,you did not state what kind of cars,I was guessing
coal hoppers.If you were,here is how they work.Notice two things on these cars,first what looks like a little paddle that is on opposite sides of the car,then an extra air tank and if you look close enough
you will also see a cylinder mounted on the center sill on the "A" end.The extra air hose on thse cars is for these air tanks and comes from the locomotives main air tank.When the pressure is at a certain
PSI in the tanks and the cars are ready to be dumped,that little paddle moves out and is 90 degrees to the car.At the dump site there is a post the same height as these paddles that is carrying 24 volts DC,when the paddle and this post connect the power goes to a solonoid
on the car,which lets air from the tank into the cylinder to open the doors.After the load dumps the air pressure is changed (reversed) to
let the paddle close and the cylinder close the doors.Notice the springs on the doors,they are on a cam,that rolls over center to
positivally lock the doors. DON'T EVER get near the doors while operating,they can cut you in two!
Hope this is not too long,it is hard to describe.

Mike;
A couple of other methods which also include using main reservoir air are the rapid discharge coal hoppers which have a trip trigger on the side of the car which when pressed while passing a device set to trip them causes the air to open the chutes underneath.

Now on our ballast cars here we have remote control devices to dump the ballast. Each car has an assigned number and gate and these are tripped using a remote control device. That got the maintenance crews away from the hazardous dust that rolls off the rock as it drops.

Bob K.

Some bottom-dump coal hoppers are indeed air operated; they are easy to spot, as each car has two air hose connections at each end. They are far enough apart so that they can't accidentally cross-connected, although there have been a few embarassing accidents<g>.

Most bottom dumps more than 15 years old are equipped only for hand-opening, using anything from the tool made for the purpose to an ordinary crowbar (ain't easy, but it can be done).HOWEVER, few are still dumped by hand, instead the cars are rotary dumped, either uncoupled one or two or three at a time, depending on the size of the dumper, or coupled if they have been re-equipped with rotary couplers.

lowwater

*cough cough* *gag* *weez* *cough*..........

What are *cough* *cough* you talking ab *cough* *gag* bout??

YM



> Now on our ballast cars here we have remote control devices to
> dump the ballast. Each car has an assigned number and gate and
> these are tripped using a remote control device. That got the
> maintenance crews away from the hazardous dust that rolls off
> the rock as it drops.
>
> Bob K.