Helper Engines

[Rick-MONON]

Been reading the manual around page 46, but still having an issue.

I want to disconnect the two helper engines at the rear of the train.

I come to a stop, disconnect and the train will not move forward after I disconnect.

Is there a sequence of events to do before disconnecting the helper engines?

[crstagg]

Uncoupling disconnects the brake hoses. So you have to reinitialize the brakes.

Go to the F5 HUD display that shows Brake Information. Then bring up the F9 Train Ops display. Scroll to end of the consist and disconnect/uncouple the last item (ENG or WAG) and see what happens to the brakes. Remember it is Air Pressure in the brake hose that keeps the Brakes released. Brake the air hose connection and loose the pressure.

What you need to do to prevent the loss of Air when you uncouple is to select the ENG/WAG before the one you are going to uncouple and close the rear angle cock before uncoupling. Then you don't loose air when you uncouple. You should also set the hand brakes on the ENG/WAG you are going to uncouple from. That's why they call the person doing the job brakeman not couplerman.

[Rick-MONON]

Thanks, will give it a try.........

[P834C]

Remember it is Air Pressure that keeps the Brakes released.

I'm sure what you wrote is not exactly what you meant.

It works like that on a truck or bus but not on railroad freight cars.

In 1872, George Westinghouse invented the automatic air brake by inventing the triple valve and by equipping each car with its own air cylinder. Air pressure is maintained in the auxiliary reservoirs and in the train pipe at all times when the brakes are not applied. An equilibrium of air pressure is maintained in the train pipe and in the auxiliary air cylinders.

To apply the brakes to all of the cars at about the same time, pressure is released from the train pipe, causing the triple valve on each car to apply the brakes. To release the brakes on each car, pressure is increased in the train pipe until an excess pressure above that of the pressure in each auxiliary cylinder is reached, which throws the triple valve so as to close the inlet to the brake cylinder and open the inlet to the auxiliary reservoir from the train pipe, thus allowing the equilibrium of the two pressures to be reached.

So to add to the above once all of the auxiliary and emergency tanks on the freight cars are filled then the air in the trainline (brake pipe) becomes a signal sender. If the trainline pressure reduces by a minimum of 2 psi then the triple valves open and allow air to pass from the auxiliary tanks to the brake cylinders. If the trainline pressure increases then the triple valve re-configures to allow the trainline to charge the auxiliary tanks. Now if the trainline pressure decreases rapidly then the triple valves detect that and open both the auxiliary tank and emergency tank sending all of the air quickly to the brake cylinders. The same thing can happen when an angle cock is opened too fast.

So there are no "springs" attached on a freight car air brake system.

[crstagg]

Yes and it is the Sudden LOSS of pressure in the Train pipe that causes the Triple valve to apply the brakes. I was referring to what Rick was doing by just uncoupling without closing off the brake pipe before uncoupling causing Emergency Braking.

And I did not use the word "SPRINGS" at all.

[P834C]

And I did not use the word "SPRINGS" at all.

My springs attached reference was not directed at you and was intended as a general information statement clarifying that there is a difference between road vehicle brake systems and railroad brakes. You did say Remember it is Air Pressure that keeps the Brakes released which isn't true in any way, shape, or form. Actually when the air pressure in a freight car bleeds off (because of no air) the brakes release. Previous to the air pressure bleeding off wouldn't there be air pressure keeping the brakes set? See the confusion using the statement the way that you did?

Yes and it is the Sudden LOSS of pressure in the Train pipe that causes the Triple valve to apply the brakes.

You used the word "and" as if you are adding to what I wrote when my information above covers what needs to happen for a triple valve to do anything. A sudden loss of pressure or as I said a above a rapid decrease of pressure causes the triple valve to open the auxiliary and emergency tank valves which then sends air to the brake cylinders. I'll say it again. Once an individual freight car's air system is charged the brake pipe becomes nothing but a signal sender as the triple valve does all of the necessary redirecting of air for applying and releasing the brakes. Understanding the signal sender part is very important in the real world of train operations.

crstagg I assumed since you have been on the forums for a long time you know how things work which is why I said I'm sure what you wrote is not exactly what you meant and I knew you were giving Rick-MONON basic information. Further information was provided so others who may read the thread understand how things work.

No need for you to get mad.

[OTTODAD]

I would like to suggest that anybody who is interested in factual information on anything does a search for it in GOOGLE to read about what the horse's mouth has to say !

[P834C]

Otto:

What is the purpose of your post? I'm an Engineer with the railroad OK?

[Don6218]

If all this isn't enough, go to the Wabtec pages.

In OR, close the stupid cock and carry on.