A Treatise On The Principles And Practice Of Dock Engineering

LIVE LOAD. 425 due to a long train, in a swing bridge, the span of which is small, the contingency of a continuons line of engines upon the bridge should be provided for. The following table gives a statement of the weight of some recent locomotives and their tenders :— T A BT,K XXXTTI.—Weight of Modern Locomotives.* Weight Weight per Foot Name of Railway. Length Wheel Total per l’oot Run of Over All. Base. Weight. Run Wheel Over All. Base. Feet. Feet. Tons. Tons. Tons. Passenger engine, 53-2 44-1 85-48 1 61 1-95 Midland,1 . Goods engine, 49-7 37 0 76-46 1 54 2-03 Tank engine, 33'4 22-0 51-02 1-58 232 London and North-) Passenger engine, Goods engine, Tank engine, 51-7 51-8 44'0 39'8 80-50 75-85 1-56 1-46 1-83 1-91 Western,1 . 33'7 22-4 52-30 1-56 2-35 LancashireandYork- [ Passenger engine, Goods engine, 50'0 48-7 40'9 36'0 70-92 68'25 1-40 1-40 1-72 1-90 shire,1 . . .1 Tank engine, 38-7 24-3 59 15 1-53 2-43 r Passenger engine, 56'5 40'5 91-90 1-62 1-97 North-Eastern,1 . Goods engine, 50 1 47-9 75-65 1-51 2-00 Tank engine, 359 22-5 55*22 1-54 245 Passenger engine, 57’5 47-5 84-65 1-47 1’78 Great Western,1 .| Goods engine, 57'9 48'9 93-00 1-61 1-91 Tank engine, 30-4 15-5 47-00 1’55 3’03 Belgian State,1 Prussian State,4 Passenger engine, 57’3 49-0 104-21 1-82 212 Goods engine, 32-6 56-40 1-73 4-40 Swedish State,8 Tank engine, 130 57'00 Union Pacific. U.S A.,2 Passenger engine, 260 82-25 3'16 Chicago and North- ) 27 0 71 50 2-65 Western, U.S.A.,2j Pennsylvania, ,, -‘-^ Passenger engine and tender, 47'5 77-25 1-63 From the preceding table it will be seen that the ordinary concentrated rolling load incurred by bridges in the United Kingdom at the present time may be taken at from 30 to 35 cwts. per foot run for each line of rails. In view of the likelihood of heavier developments, however, in the future, 2 tons or even 2| tons would be by no means an excessive allowance. Even these figures are exceeded in certain cases, as is evident from a table f prepared by Mr. Alexander Boss, the engineer to the Great Northern Railway Co., of which an abridgement is given below. The table shows the equivalent uniformly distributed live loads derived from the maximum • Note.—These statistics are derived from the following sources :— 1 Fair on “ Moving Loads on Railway Underbridges,” Min. Proe. Inst. C.E., vol. cxli. 2 Leigh on “ American Passenger Locomotives,” Min. Proc. Inst. C.E., vol. cxlvi. 3 Trautwine’s Civil Engineers’ Pocket-Book. 4 Von Borries on “ Prussian State Railways,” Min. Proc. Inst. C.E., vol. cxxii. 5 Teknisk Tedskrift, Stockholm, Oct. 31, 1901, and Min. Proc. Inst. C.E., vol. cxliv., p. 340. + Ross, on “ Railway Bridges,” Eng. Conf., 1903, vide Engineering, June 19, 1903.