FORTY-TWO MILES PER HOUR.
Nearly every person that we hear speak of travel by rail, thinks that he has, on numerous occasions, traveled at the rate of sixty miles an hour; but among engineers this is known to be an extremely rare occurrence. I myself have run some pretty fast machines, and never had much fear as to "letting them out," and I never attained that speed for more than a mile or two on a down grade, and with a light train, excepting on one or two occasions. Supposing, however, reader, that we look a little into what an engine has to do in order to run a mile in a minute, or more time. Say we go down to the depot, and take a ride on this Morning Express, which goes to Columbus in one hour and thirty-five minutes, making two stops. We will get aboard of the Deshler, one of the smartest engines on the road, originally built by Moore & Richardson, but since then thoroughly overhauled, and in fact rejuvenated, by that prince of master-mechanics, "Dick Bromley." And you may be sure she is in good trim for good work, as it is a habit with Dick to have his engines all so. She is run by that little fellow you see there, always looking good-natured, but getting around his engine pretty fast. That is "Johnny Andrews," and you can warrant that if Dick Bromley builds an engine, and Johnny runs her, and you ride behind her, you will have a pretty fast ride if the time demands it. The train is seven minutes behind time to-day, reducing the time to Columbus—55 miles—to one hour and twenty-eight minutes, and that with this heavy train of ten cars, all fully loaded. After deducting nine minutes more, that will undoubtedly be lost in making two stops, this will demand a speed of forty-two miles per hour; which I rather guess will satisfy you. You see the tender is piled full of wood, enough to last your kitchen fire for quite a while; but that has got to be filled again; for, ere we reach Columbus, we shall need two cords and a half. Look into the tank; you see it is full of water; but we shall have to take some more; for between here and Columbus, 1558 gallons of water must be flashed into steam, and sent traveling through the cylinders.
But we are off; you see this hill is before us; and looking behind, you will see that another engine is helping us. Notwithstanding that help, let us see what the Deshler is doing, and how Johnny manages her. She is carrying a head of steam which exerts on every square inch of the internal surface of the boiler, a pressure of 120 pounds. Take a glance at the size of the boiler; it is 17 feet 6 inches long, and 40 inches in diameter. Inside of it there is the fire-box, 48 inches long, 62 inches deep, and 36 across. From this to the front of the engine, you see a lot of flues running. There are 112 of these, 10 feet 6 inches long, and two inches in diameter; and of the inner surface of all this, every square inch is subjected to the aforesaid pressure, which amounts to a pressure of 95,005 pounds on each flue. Don't you think, if there is a weak place anywhere in this boiler, it will be mighty apt to give out? And if it does, and this enormous power is let loose at once, where will you and I go to? Don't be afraid, though; for this boiler is built strongly; every plate is right and sound. Open that fire-door. Do you hear that enormously loud cough? That is the noise made by the escape, through an opening of 31 square inches only, of the steam which has been at work in the cylinder. You can feel how it shakes the whole engine. And see how it stirs up the fire. Whew! isn't that rather a hot-looking hole? The heat there is about 2800° Centigrade scale. But we begin to go faster. Listen! try if you can count the sounds made by the escaping steam, which we call the "exhaust." No, you cannot; but at every one of those sounds, two solid feet of steam has been taken from the boilers, used in the cylinder, where it exerted on the piston, which is fourteen inches in diameter, a pressure of nine tons, and then let out into the air, making, in so doing, that noise. There are four of those "exhausts" to every revolution of the driving-wheels, during which revolution we advance only 172⁄3 feet. Now we are up to our speed, making 208 revolutions, changing 331⁄3 gallons of water into steam every minute we run, and burning eight solid feet of wood.
We are now running a mile in one minute and twenty-six seconds; the driving-wheels are revolving a little more than 3½ times in each second; and steam is admitted into, and escapes from, the cylinders fifteen times in a second, exerting each time a force of nearly nine tons on the pistons. We advance 61 feet per second. Our engine weighs 22 tons; our tender about 17 tons; and each car in the train with passengers, about 17 tons; so that our whole train weighs, at a rough calculation, 209 tons, and should we strike an object sufficiently heavy to resist us, we would exert upon it a momentum of 12,749 tons—a force hard to resist!
Look out at the driving-wheels; see how swiftly they revolve. Those parallel rods, that connect the drivers, each weighing nearly 150 pounds, are slung around at the rate of 210 times a minute. Don't you think that enough is required of an engine to run 42 miles per hour, without making it gain 18 miles in that time? Those tender-wheels, too, have been turning pretty lively meanwhile—no less than 600 times per minute. Each piston has, in each minute we have traveled, moved about 700 feet. So you see that, all around, we have traveled pretty fast, and here we are in Columbus, "on time;" and I take it you are satisfied with 42 miles per hour, and will never hereafter ask for 60.
Let us sum up, and then bid good-bye to the Deshler and her accommodating runner, Johnny Andrews. The drivers have revolved 16,830 times. Steam has entered and been ejected from the cylinders 67,320 times. Each piston has traveled 47,766 feet, and we have run only 55 miles, at the rate of 42 miles per hour.
USED UP AT LAST.