This is something that has puzzled me, I am familiar with air brake systems on highway trucks, air pressure is required to keep the brakes in the released position, if the system fails and air pressure is lost the the brakes activate stopping the truck. If an air brake trailer is parked then it has no air pressure and therefore cannot move. Very simple.
Now I would expect trains to be the same, but if that was the case then the cars couldn't be moved without a train providing air pressure, and that I know is not the case. So if the car moves with no air pressure then surely the air is needed to activate the brakes, (or brake wheel on a siding).
So does the locomotive provide air pressure to activate the brakes? then how does the loco stop if air pressure is lost? I am sure it has to be more complicated than this.
Does a yard switcher hook up air hoses when moving cars? or not.
An explaination of this would be appreciated. Martin
Now I would expect trains to be the same, but if that was the case then the cars couldn't be moved without a train providing air pressure, and that I know is not the case. So if the car moves with no air pressure then surely the air is needed to activate the brakes, (or brake wheel on a siding).
So does the locomotive provide air pressure to activate the brakes? then how does the loco stop if air pressure is lost? I am sure it has to be more complicated than this.
Does a yard switcher hook up air hoses when moving cars? or not.
An explaination of this would be appreciated. Martin