. The Street railway journal . ercentage, which varies according totraction resistance, while the speed is maintained practicallyconstant. The practical value of this peculiarity has veryoften been doubted. However, the respective tests not onlyproved the possibility of recuperation, but settled at the sametime the quantity of energy which could be gained. On a sec-tion with a down grade of 2 per cent, with a 120-ton train anda speed of about 30 km per hour, watt-hours—that is,about 80 per cent of the energy—have been recovered whichotherwise would have been lost in braking. The exceeding
. The Street railway journal . ercentage, which varies according totraction resistance, while the speed is maintained practicallyconstant. The practical value of this peculiarity has veryoften been doubted. However, the respective tests not onlyproved the possibility of recuperation, but settled at the sametime the quantity of energy which could be gained. On a sec-tion with a down grade of 2 per cent, with a 120-ton train anda speed of about 30 km per hour, watt-hours—that is,about 80 per cent of the energy—have been recovered whichotherwise would have been lost in braking. The exceedinglyfavorable result in regard to energy consumption of the Val-tellina is due chiefly to this circumstance. The question as to how to utilize the energy thus gained haslikewise often been discussed. The simplest solution wouldevidently be to equip with electric traction not only the steepgrades of mountain lines, but also the adjoining level sections, Speed per hour: 31 Km. Drawbar pull: 8000 resistance: 4 Kg. nied, either, in the case of main railways, inasmuch as bothexpress and local trains must be stopped rather frequentlyfrom a high running speed. The acceleration of these trainsrepresents an important part of the total energy simple cascade working 35 per cent to 40 per cent ofthis energy, as above mentioned, may be saved; with four-stepcascade connection even more. In the case of hydro-electric power stations, the energy re-cuperation is so far of importance that it allows the operationof a longer line or heavier trains from the same plant thanwould be the case without recuperation. With steam plantsthe saving is shown in operating cost. ENERGY CONSUMPTION AS A FUNCTION OF GRADESFor a certain speed the energy consumption may be repre-sented very simply as a function of the grade. Assuming thatthe motors work with an efficiency of 100 per cent, the energy Speed per hour: 02 Km. Drawbar pull: 5000 resistance: G Kg Ton. 150 110 130 1
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
