Joule Rail Car Stopper

Joule Rail Car Stopper (US Patent: US 8,485,106 B2)

The stopper is intended use is to slow and arrest the first car reaching the end of a classification track to 0 mph (0 m/s) and positively restrain the car in place. Typical classification tracks have prevent roll out incline grades better than 0.30% which facilitates grade deceleration. Coupling speed in the USA is 4 mph (6.4 km/h, ± 1.80m/s), and in Europe typically 0.8m/s to 1.0m/s, and hence the concept was developed to bring a rail car of 140 ton (127,000 kg) to a stop from 4 mph (6.4 km/h, ± 1.80m/s), to 0 mph (0m/s, 0 km/h).

The stopper can also be used in tippler applications to hold cars stationary at the entrance to the tippler, or at the exit.


In marshalling yard applications. Once the first car is stopped consecutive cars will couple and as the train builds the impact forces will be dissipated by the couplers, and the combined stationary mass of the cars already arrested.

The stopper is mounted below the rails in a steel tub tightly compacted into the sub grade, and all the force is transferred into the surrounding subgrade during operation.


The rail car wheel flange is the point of contact with the contact rollers on the stopper shaft. The rollers on the stopper shaft rotates under impact to prevent wheel climb.

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