almo Wrote:
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> Kind of meant that if the air connection between
> the loco and railcars could be cut (or damaged) in
> a way to leak out the air in the brake lines. The
> air brakes rely on built-up air pressure to remain
> "open" - correct? Even if the locomotive's
> automatic safety features did not detect an air
> leak, could the brakes of the train be enough to
> stop a runaway?
>
> almo


If the locomotive is still operating it will have an air compressor recharging the brake pipe pressure at about the same rate as any cut. No trains of any length have a completely leak free brake pipe under normal situations. A large leak (bigger than what can be recharged by the air compressor) works the same way as a brake pipe reduction made by an engineer. Depending on many factors it could slow a train maybe stop it. If your on a runaway train and can cut an air hose you might as well cut it enough to trigger an emergency brake application. Any and all cars brake valves (not just the locomotive) will detect the sudden loss of air pressure and initiate an emergency application.

How the brake systems work is a complicated science and would take forever to fully explain it here. Its not really like a truck. Read this to help understand it. http://www.railway-technical.com/brake2.shtml