CHAPTER VIII.
RUNNING A FAST PASSENGER TRAIN.
Materials for the following notes were taken during a trip on the Pennsylvania Railroad:—
AVERAGE SPEED.
The New York and Chicago limited express train, run on the Pennsylvania system of railroads, passes over the distance of 912 miles between the two cities in twenty-five hours and twenty-nine minutes, making an average speed of 35.29 miles an hour. All the known resources of mechanical science have been ransacked to produce appliances for reducing delays, so that the highest possible percentage of the time provided for the journey should be devoted to running. Water for steam-making is collected, as the train runs along, from troughs placed in the middle of the track; a system of absolute block signals, controlled by vigilant train-dispatchers, provides a clear line; and stops are made only for the purpose of changing the locomotives at the end of divisions. The lines over which the train runs traverse a multitude of cities and towns, most of them having the streets crossing the track on the level; and a great many other railroads are crossed at grade. Therefore, although the actual stops between Jersey City and Chicago are only seven, a run exceeding ten miles without meeting with the necessity of checking the speed is rare.
SPEED BETWEEN JERSEY CITY AND PHILADELPHIA.
The run of ninety miles from Jersey City to Philadelphia is made at an average speed of 45 miles an hour, leaving an average of 34 miles an hour for the remainder of the journey. To keep on time, some parts of the first division must be traversed at a speed over 60 miles an hour, while 50 miles an hour must be maintained over a considerable portion of the other divisions.
REQUISITES OF A HIGH-SPEED LOCOMOTIVE.
The first essential for a high-speed locomotive is the means of generating steam freely as fast as it is used up by the cylinders. The next consideration is properly designed steam-distribution gear, and well-proportioned machinery, so that the heat energy produced by the boiler may be converted into useful work in propelling the engine with the least possible loss of power. To handle the fast trains between New York and Philadelphia, the mechanical talent of the Pennsylvania Railroad, aided by fifty years’ inherited experience, has produced the form of engine known as Class K. This is an anthracite-coal-burning locomotive, with 1,205 square feet of heating-surface to supply steam to cylinders 18 inches by 24 inches, which turn two pairs of coupled drivers 78 inches in diameter. The traction force of the engine is thus (182 × 24)/78 = 99.69 pounds for each pound of effective pressure per square inch of the pistons. The valves are the plain slide, with 1¼ inch outside lap, no inside lap, 1/16 inch lead in full gear, and a full travel of 5½ inches. The steam-ports are 16¾ inches long and 1½ inches wide; while the exhaust port is 3¼ inches wide, securing free emission of steam.