On 2010-06-15, danmitch wrote:
Ignoramus9619 wrote:

Dan, awesome post, thanks a lot for educating me.
You are quite welcome.

Train air brakes are a very complicated affair. Due to the long length
of the train-line, a delay exists between the action of operatign of the
valves in the locomotive, and the actuation of the braking action at
each car. The longer the train, the greater the delay toward the back of
the train. Hence the engineer must anticipate actions ahead of time.
This reqires experience, and a prior knowledge of the "profile" (grades)
of the track being operated over. Incorrect brake operatin can either
break the train in two (breaking couplers or pulling drawbars), or
result in a loss of control of the whole train.

Some work is being done on "electric" brakes for trains (probably still
air actuated, but electrically controlled) ... these would have faster
response to commands, but the technology is yet unproved. Air brakes,
while complicated and smoetimes troublesome, are a proven technology.
So, there's some resistance to change.

Dan, write something else about trains. I love reading this stuff. I
am a somewhat of a train fan and one of my kids (4 year old) is an
avid train fan, so we go see trains a lot.

As for brakes, I thought that the brake system is a lot simpler, that
air holds brakes away from the wheels, and when air comes out, the
brake pads touch wheels. Now I know that it is more complicated.
i