What it takes to stop a train from 45 mph

Trains have a reputation for being big, heavy, and hard to stop. But just how much does it take to stop a fully loaded freight train?

This UP double stack train was put into full emergency stop when an air line ruptured. On a standard train all the cars are connected on a single air line that operates the brakes. A compressor in the engine charges the line, increasing pressure in the line decreases pressure on the brakes. A fully charged (brakes fully off) line is in the 70-90 psi range. If this brake line separates the loss of pressure automatically applies full braking force on each car on the train.
TL;DR: separating an air line results in the hardest a train can brake.

Now for some numbers:

The first number requires no math. It took one minute and four seconds for this train to come to a complete stop.

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Next, establishing the speed. The three locomotives in front are 71 feet each. it took about 3.25 seconds for all three to pass the right edge of the frame. That gives us a speed of 65.5 feet per second, or 44.7 mph.

And lastly, distance. Rail manufacturer Greenbriar puts their double stack cars at 76.75 feet long. 39 cars pass by from the time of brake application to the time the train finally stops. That gives a stopping distance of 2,993 feet. More than half a mile.

So, put simply, a large freight train like this, under maximum brakes, still requires over a minute and roughly 3,000 feet to come to a stop from 45 mph

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