compensates for an equal height of ascending grade, we have 93.99 feet rise in 24.695 miles, and the co-efficient of resistance becomes All the data of the three runs are brought 1 6.62 per ton, say The total resistance of the locomotive, ascertained by experiment to be equal to 33.38 indicated horse-power, which is 9.9 per cent of the mean total indicated power (337.17 indicated horse-power), made up of two parts: first, the resistance of the wheels on the rails, 1 which, at its mean value, 6.688 pounds per ton , 334.9 amounts to 17.23 indicated horse-power, equal to 5.11 per cent, leaving 16.15 indicated horse-power, equal to 4.79 per cent of the total mean indicated horse-power, as the sum of the internal frictions of the engine when propelling only itself and its tender, 49.174 tons, at mean velocity. The respective speeds were: for part of the first run, No. 13 to No. 31, ascending grade 18.21 feet per mile, 14 miles per hour; for the entire first run, ascending 182.14 feet, then descending 88.15 feet, net rise 93.99 feet, mean grade 3.809 feet per mile, 17.23 miles per hour; second run, ascending grade 6.683 feet per mile, 22.67 miles per hour; third run, ascending grade 3.837 feet per mile, 20.496 miles per hour. The mean speed, mean net rising grade 3.809 feet per mile, was 19.431 miles per hour. These figures indicate that the rolling resistance of this train was less than it is given in D. K. Clark's tables, than which nothing is more likely. But this whole subject has been too little studied, and the writer has devoted to this trial more time than he could have done if it were not almost alone in this field. Some examples of locomotive performance, which the writer has taken no little pains to verify, will close this portion of our subject. Locomotive No. 137, Boston and Albany Railroad, built in the repair-shop of the company at Boston, under the charge of Mr. George H. Colby, division master mechanic, was placed in service April 23, 1883, and after running seven days to Worcester, 44 miles and return, making 616 miles, was put, on April 30, into regular express-train service between Boston and Springfield, making the round trip in 6 hours, about 3 hours each way. The distance, commonly called 100 miles, is, by measurement, 98.63 miles, making the round trip 197.26 miles. She continued in this service until July 10, 1884, 14 months and 11 days, say 438 days, with the loss of only 2 days for trivial repairs, — in one case, the tightening of an eccentric, but made some extra runs, so that her mileage was in all 87,190 miles, making her daily mean for the 438 days 197.65 miles, at the rate of 72,192 miles per annum; and for the 436 days of actual service, 198.11 miles. On the 10th July, 1884, she was taken into the shop; and in the four days, July 11, 12, 14, 15, without any work on nights or on Sunday, her tires were turned, her valves faced, and all parts were put in perfect order, including painting and varnishing all over; and on the 16th she resumed her regular service. The road is very crooked, and presents curves of 573 feet radius (10° curves); and although the western end of the route is only 60 feet higher than the eastern end, the rise to the summit, 57.25 miles from Boston, is 893 feet, and the descent thence to Springfield, in 41.38 miles, is 833 feet, making the mean rising grade, going west, 15.5 feet per mile, and going east, 20.13 feet; and there are several inclines, 3 to 5 miles in length, of 38 to 60 feet per mile. The train comprised 2 baggage and express cars, 4 sleeping-cars, and 3 to 5 first-class long passenger-cars, usually weighing and often exceeding 300 tons, -say 672,000 pounds, locomotive and tender included. From May 1, 1883, to July 1, 1884, a period of 14 months (427 days), this engine has a record of 84,596 miles, - 427 round trips, with a total consumption of coal equal to 1,965.625 tons, 4.603 tons per round trip, 52 pounds per mile, 0.1733 pounds per ton per mile, 1,718.6 pounds per hour, and a mean per hour, on each square foot of grate — up grade and down grade-of 95.48 pounds. The power could not have been less, as a mean, than 340 indicated horse-power, rising at times, probably, to 600; and the mean consumption of coal was about 5 pounds per indicated horse-power and per hour. The oil used for lubrication, in the same period, was 1,120.5 gallons, equal to 75.51 miles per gallon; and the cost of oil and waste was $622.55, equal to 0.736 cent per train-mile, and repairs would not bring the aggregate up to 1 cent. Coal was taken at Boston for the round trip. At the exorbitant price of $5 per ton, the cost of fuel per train-mile was about 11.6 cents, and per mileton, 0.039 cent. There are seven engines of this description now in use on this road, and others in construction. The leading dimensions are as follows: Cylinders, 18 inches diameter, 22 inches stroke; 4 driving-wheels connected, 68.75 inches diameter, 100 inches centre to centre; total wheel-base, 22 feet 4 inches. Boiler, wagon-top, barrel 52 inches diameter outside of small courses, inch thick, fluesheetsinch, fire-box & inch, all Nashua Company's steel; 221 semisteel tubes, 2 inches outside diameter, 10 feet 10 inches long between tube-sheets, inch apart; fire-grate area, 18 square feet; heating surface, in fire-box 130 square feet, flues inside 1,140 square feet, total 1,270 square feet. Total weight, 87,000 pounds (38.839 tons); weight on drivers, 55,000 pounds (24,554 tons); normal pressure, 160 pounds per square inch above the atmosphere, say 11.88 atmospheres, absolute. The "Pacific," built by the Lawrence Machine Shop, of which the writer was superintendent, was placed in service on the Boston and Maine Railroad, April 16, 1855, and continued to run regularly double round trips between Boston and Lawrence, distance 26 miles, daily, except Sundays, or on other equivalent routes, until the close of 1883, a period of 28 years 9 months. The record, subsequent to 1876, was destroyed by fire a year ago; but one book escaped, which shows when this engine was in the repair-shop, and the amount of repairs upon her, from the start, down to Dec. 23, 1873, 18.8 years. The superintendent of repairs on this road, Mr. William Smith, ran the Pacific" thirteen and a half years, making an aggregate mileage, during that time, of 417,879 miles. Mr. Smith is perfectly familiar with her performance since 1873; and from information obtained from him, and from the record, which I have transcribed, it appears that Her total mileage on passenger-trains, in 28.8 years, was . 891,475 And her subsequent mileage on gravel-trains, to Aug. 1, 1884, is 12,780 Total mileage 904,255 She has had one new fire-box, and one new set of flues, and other extensive repairs, and is now in good serviceable order; and more than one-half of the weight of the original material originally put into her is in her to-day. This engine has outside connections, shifting link valve-gear, cylinders 15 inches diameter, 22 inches stroke, 4 connected drivers 66 inches diameter, and a centre-bearing truck. Total weight 27.5 tons, weight on driving-wheels 17 tons. Price, in dear times, $8,500, say £1,756. The statement summarized below, of the performance of three locomotives on the Hudson River Division of the New York Central and Hudson River Railroad, was kindly furnished to the writer by Mr. William Buchanan, superintendent of motive-power of that division. The three engines, designated as No. 10, No. 33, and No. 34, are of the following general dimensions: Cylinders, 17 inches diameter, 24 inches stroke; driving-wheels, 69 inches diameter; fireboxes of steel, flues of semi-steel; weight in running order, 31.473 tons (70,500 pounds); weight on driving-wheels, 20.022 tons (44,850 pounds); average trains, 2 baggage and mail cars 52 tons, 2 drawing room or sleeping cars 64 tons, 5 first-class passenger-cars 125 tons, engine 31 tons, tender, half loaded, 22 tons; total, 294 tons. Average speed of trains, 38 miles per hour. Period of time covered, 6 years, from December, 1876, to December, 1882, for No. 10 and No. 33; and from March, 1877, to March, 1883, for No. 34. |