These wheels form excellent examples, because of the excessive duty to which they are subjected by reason of the frequency of their stoppage under the pressure of the vacuum brake.

It seems that on the train reaching the top of the bank, there was an explosion of dynamite in front of the engine, upon which the driver applied the vacuum brake; he then tried to run back, but, after climbing the hill, he had no steam left to blow off the vacuum and so release the brakes, and then, hearing another explosion in rear, he and the fireman jumped and ran, the former going north and the latter south.

New York Air Brake, founded in Watertown, N. Y. about 50 years ago to turn out a vacuum brake, got involved in patent squabbles with George Westinghouse, and the upshot was an agreement whereby New York made Westinghouse brakes under license.

Feeling what we felt then helped us to realise the retardatory force which that vacuum brake must be exerting,—it did not seem at all surprising that the train should have been brought to an almost instant stand-still.