Recent Developments. Between 1890 and
1900 the Ameiicim locomotive experienced a won-
derful development. In 1890 in America an eight-
wheeled loeomotive. with IS X 24-iii(h cylinders
and a boiler having about 2200 square feet of
heatinu surface, was in quite <;eneral use for first-
class passenger service; the weight on the drivers
seldoin exceeded 05.000 pounds, and the total
weight of the engine was usually within 100.000
pounds in working order. In freight service
engines weighing between 100,000 and 120,000
liounds on the drivers were considered powerful
locoiiHitives. To-dav passenger loconiotives, if
provided with two pairs of drivers, often have
from Sfi.OOO to 105,000 jiounds upon Ihem, and if
of the ten-wheel tvpe they have from 100.000 to
135,01)11 pounds upon drivers; the cylinders are
19 or 20 inches in diameter; the heating surface
is from 2200 to 3000 square feet, aud the grate
area is from 30 to 30 square feet, unless wide
grates are provided for burning some special
grade of coal.
Perhaps the most important developments _ m passenger locomotives have been in the direction of high sjieed; and in this the American locomo- tivesliow maintain the best records, although they have been eclipsed on several occasions by those of European railways, which usually do not main- tain their record" speeds or keep to their adver- tised schedules. The type of engine shown on the accompanying plate has attained a speed of 7.05 miles at 'the rate of 103.75 miles per hour, and 7.29 miles at the rate of 103.35 miles per hour while drawing the Empire State Express on the New York Central and Hudson River Ivail- road. These speeds were made on a total run of 80 miles, during which the average spee^l was 07. GO miles per hour with a train consisting of six cars weighing 201 tons. A similar engine with a train which with the engine and tender aggregated 731.19 tons develo])cd an average speed of 55.8 miles per hour for two hours and seven minutes. The horse-power developed by this engine was estimated at over 1900. and is, as far as known, the highest liorse-jiower ever de- veloped in passenger service.
The dimensions and other data for this engine are as follows;
HlOH-SPEED PASSENaEB LOCOMOTIVE. SCHENECTADY W0HK8.
American Locomotive Company. rcntriil .t1nntin tyjip: GaUKP. 4 tppt SVs inches. rylimlcrH. '21 iiiohps diaiiictcr, 2G-inch stroke. IM-iviTM. 7'.) iiiclH'K (liaineter. Wlii'i'l-liasi'. ilrivinn- 7 fei't. total 27 teet 3 inchPH, Wcitflit. nil drivers. fl.T.niin i)niiiiilrt, total tin. 0(10 pounds. Tank capacity. 6,(HI0 United Stales (tallons. Weight of teiiiler with coal and water. 110,500 pounds. Traction power, 24,700 pounds. Holler prt^ssure, 200 pounds.
HeatluK surface, tubes. li'J'.W.OS scpiare feet. HeatiMK svirface. water-tubes. 27.09 square feet. Ile.ifiiiK surface, flre-hns. ISO square feet. HeatiiiK surface, total. .tSOS.l? square teet. Grate area, 60.3 square feet.
A freight locomotive with 150.000 pounds on the drivers is not considered a large locomotive for ordinary road work, and for mountain ser- vice and fiir pushing on heavy grades, engines have been built with as much as 232.000 pounds, as is the case with the decapod engine shown on the accompanying plate, which can move on a level at slow speed over 10.000 tons of load, ex- clusive of weight of engine and tender. The fol- lowing table contains its dimensions and other specifications:
Tanpkm Compocnd Engine, Schenectady Works. American Locomotive Company. Decapod tvpe: (iaUKP, 4 feet «V4 indies. Cylinders. 17!.;; and;tu Inches diameter, 34-inch stroke. DriviTM. 57 Inches diameter. W'hei'l-bnse, driving' 20 feet, total 28 feet 11 Inches, Weiglit, on drivers. 2:)2,0(»i pounds, total 25U,80(i pounds.
Tank copac:ity. 7000 United .States gallons. WeiKiit of tender with coal and water, i:J4,900 pounds. Traction power 55,300 pounds, lioiler pressure 22.') pouudB. Heatinw Kurfaee. tubes. 4470.5 square feet. HeatiuK surface, flre-box. 205.4 scpiare feet. Heating surface, total. 4tWl.'J square feet. Grate urea, Gy.47 square feet. In general, the tendency everywhere is toward larger locojnotivcs. The accompanying tables give the main dimensions of a number of the heaviest freight and passenger locomotives which have been built in the L'nited States during recent j-ears. European locomotives diflor from those used in America chiefly in the following particu- lars: The American locomotive has a bar frame and carries its cylinders outside of the frame, while English and many European locomotives have a plate friune and 'usually carry the cylin- ders inside of the frame. The frame of the American engine usually rests on the wheel* through the medium of equalizing springs, while equalizing springs are but seldom used on Euro- pean engines. Eight-wheel tenders are universal in America, while four-wheel and six-wheel ten- ders are used in Europe. The roomy cabs with seats for the driver and fireman were for many years peculiar to .merican engines, but are grad- ually being adopted on the Continent of Europe. LonciiNG Locomotives. The locomotives or- dinarily known as logging locomotives are of two types. ' One is built after the general pattern of the four-wheeled switching locomotive, with the exception that the wheels have broad grooved tires a foot or so in width that are adapted to running upon a track formed of logs placed end to end. The other is known as the Shay loco- motive and is fitted to run on ordinary rails. Such an engine is shown in I'ig. 16. It is built on three four-wheeled centre-bearing swivcled trucks, the wheels of which arc driven by bevel gearing attached to the right-liand wheels of each truck with steel pinions meshing into them, carried by a shaft running in bearings attached to the journal-boxes, and extending from axle to axle of each truck. The power is communi- cated in these pinion shafts with flexible coup- lings extending from the engines, which are placed vertically on the side of the boiler. This arrangement leaves each truck free to adjust it- self to curves and irregularities of the track. The three trucks here spoken of include the tender truck, which is a driving truck also. The trucks are built of steel, are equalized, and have coiled springs. The object of this construction is to have the shortest possible rigid wheel-base and the longest possible flexible wheel-base, thus utilizing all the weight for traction. It is possi- ble to work the locomotive on very sharp curves, the one illustrated running easily on a G5-dcgree curve. Its use is confined tq roads having heavy grades and sharp curves, and it is restricted to low speeds. The frames of both engine and tender are made of 10-inch I-beams, one on each side, that of the engine being strengthened by a truss-rod as shown. Steam brakes are provided . to act on part or all of the drivers, either
separately or together.
