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The Westinghouse Air Brake

(By R. E. R.)

After the steam locomotive, the Westinghouse Air Brake may be ranked as the next most important invention associated with railways. Its services in the protection of life and property are unique. By its adoption trains were enabled to run faster, more safely, and to be stopped in a much shorter distance.

In ordinary service it requires several minutes for a train starting from a standstill to be accelerated to a speed of about 30 miles an hour. But should the automatic brake be applied when the train is moving at its highest speed, it can be brought to a stop in a few seconds of time and in a few feet of distance. Consider one of the Westinghouse brake tests carried out in New Zealand some years ago. A train weighing 212 tons and running at a speed of 33 miles per hour was stopped in 16 seconds and in a distance of 330 feet. The amount of power required to keep this train moving at a speed of 33 miles an hour would be about 17,000,000 lbs., and it would take about the same amount of power to bring the train to a standstill.

In actual service the Westinghouse Air Brake on a train is much more powerful than the engine that is hauling the train. Thus, though the engine may be in full steam and be exerting its maximum power, the train will immediately stop if the air brakes on the train are fully applied.

Although the working and manipulation of the air brake is very simple and the brake is always ready for action, it is advisable in train service, when trains are running between important stations, to make as few stops as possible. Each train stop adds to the cost of running the train, and by cutting out unnecessary stops, and also by shortening station and other train stops, a considerable saving of expense as well as of time, can be effected.

In the old days when only hand brakes were in use, both the engines and the trains were fitted with wooden brake blocks. Later, cast iron brake blocks came into service (one on each wagon). This was before the Westinghouse brake was invented or brought into general use. It was then often necessary for the engine-driver to make preparations for stopping the train a considerable distance away from the station or stopping place. When running down grades all hand brakes were generally pinned down and the enginedriver was never sure where the train would eventually stop. Even in those early railway days, the enginedriver did some really fine work. At that period the extra time required to stop the trains meant a larger consumption of coal and water, besides making the whole journey longer.

After the Westinghouse brake came into service the trains were speeded up and the distance of the train stop was very considerably shortened thus lessening the time for the train journey. The stopping cost of trains involves such questions as the amount of coal and water consumed; the wear and tear of the brake blocks, brake gear, etc.; the length of time the train is standing at the station; and the amount of power required to re-start the train.

Train stop costs were carefully calculated in the United States some years ago and the following is an endeavour to bring these costs up to date. The figures (approximate) are for passenger trains of seven and eight cars, of a total weight including engine and tender, of 530 tons and running at 50 miles per hour:

With any trains, it is an economical factor and good railway practice to run a journey with as few stops as possible, through trains if fully loaded being the most payable. The continual stopping and starting of trains has a considerable bearing on the life of the rolling stock. This can be readily understood when we take into consideration the strains and stresses that take place in the draw gear when a train is being started. These strains and stresses are not lessened until the train has been working for some time and the velocity of the vehicles has become uniform—factors which apply also to trains that are being stopped.

When trains are equipped with automatic power brakes, it is possible to keep them moving at a fairly high speed when entering railway stations and to make a good train stop in a very short distance, thereby saving time. A quick brake release can also be made, enabling the train to start promptly. When travelling down grades the speed can be kept safe and page 71 uniform, and, if necessary, the train can be stopped on any part of the grade.

Some years ago a train weighing about 1,000 tons was safely controlled down one of the steepest railway grades in New Zealand, and a small part only of the air brake force was utilised during the whole operation.

In the United States—the country of long and heavy trains—trains of 17,000 tons are being safely handled. (The United States ton is 2,000 lbs.)

In nearly every country of importance the railway authorities are endeavouring to increase the tonnage, speed, and length of trains. In every case the safety appliances are progressing and keeping pace with general railway advancement. Without the use of the automatic air brake and other safety appliances, this progressive policy could not be carried out. Generally these improvements are costly, and the upkeep considerable, but it is a paying policy as it enables the railways to handle heavier and longer trains and to give quicker service and delivery.

Moreover the provision of safety appliances is an insurance against accident. One serious railway accident may be a calamity, involving the loss of human life and destruction of rolling stock. The Westinghouse Air Brake, properly installed, well cared for, and efficiently handled, as it is in New Zealand, is a tremendously important factor in the safe operation of trains.

I was travelling on an express train a short time ago, when the enginedriver of the train remarked to me: “Well, the Westinghouse brake saved me two accidents this morning. There were two slips on the line and I was able to stop in time.” While the travelling public may grumble at little inconveniences or delays that will at times occur, they should remember that the New Zealand Railway Department (and this includes the whole railway staff), are doing all they possibly can to make railway travelling safe and comfortable. Our slogan is “The safety of the public” and the safety record of travel by rail in New Zealand proves how effectually this slogan functions.