Transactions of the Institution of Civil Engineers Volume 3, PT. 2

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1840 Excerpt: ... the dead stoppages, amounting to 88 minutes, from the whole time, the actual period occupied in travelling was'7 hours, 3 minutes, 59 seconds. The total evaporation was 39812lbs. effected in 512 minutes; the proportion for the actual time of the trip, or 424 minutes, 32937 lbs.; difference 6875 lbs. The dead stoppages are divisible into two portions, viz. 9 very short ones comprising 31 minutes, 40 seconds; and 2 long ones equal to 56 minutes, 49 seconds. For the short stoppages I have deducted the full proportion, or 2465 lbs., as the steam would blow on the instant of stopping, perhaps even whilst the engine was coming to rest at the several stations, the regulator being closed some instants before arriving at them. The two long stoppages at Warrington averaged each 28 minutes, 24 seconds, but though, at the moment of stopping, the fire would be of the same intensity as during motion, it would be greatly diminished in force at the moment of starting again; for those two delays, therefore, a different correction is required as regards waste of steam. This I have endeavoured to supply. Mr. Woods has informed me that the usual consumption of coke by engines waiting to start at the termini is about 100 lbs. per hour. This is an useful fact, as it determines, approximately, the difference in the rates of combustion and evaporation by locomotive boilers with the simple draught of the chimney, and with the acceleration given to it by the blast. Their difference on the Hecla, at the velocity of the journey, is about 8 to 1. If the evaporation for the whole delay at Warrington were reckoned as proportional to the time, with an active blast, it would amount to 4416 lbs.; and if computed according to the evaporative power of the boiler, without the blast, it would ...