MECHANICS AND USEFUL AKTS. 37 



the other, or supposing the speed to be diminished on the gradient 

 to 17 miles an hour, to but 50 horse-power. The carriage is not 

 of the omnibus kind, but has 7 compartments, and guards- 

 van, in all respects in conformity with the standard rolling stock 

 of the English lines. The weight being in no case greater than 

 two and one-half tons per wheel, lines of corresponding lightness 

 would serve as well as heavy lines now serve for heavy engines, 

 loaded as they are from 5, 6, 7, and even 8 tons upon each driv- 

 ing-wheel. If even half filled with passengers, such a carriage 

 at ordinary fares would earn about 5s. per mile, and if filled about 

 twice as much. The whole cost of working would be small. 

 When working upon moderately easy gradients, the consumption 

 of coal would run but from 6 to 8 lbs. per mile, the wages of 

 stoker, driver, and guard making 100 miles a day, to l|d. per 

 mile, including all train charges. Peraianent way, station ex- 

 penses, and general expenses might carry the whole to Is., or 

 Is. od. ; but even at twice the last-named cost, there would be 

 a high proportion of profit on the work. The motion of the 

 carriage is easier than that of an ordinary train ; the total wheel- 

 base being so much longer and yet so much easier from being 

 formed upon swivelling bogies. It is ahnost impossible to im- 

 agine that if branch-line and other short trafiic passengers were 

 allowed to use this carriage, they would not universally pro- 

 nounce in its favor. Mr. Fairlee, the designer, having worked 

 out his system upon the great scale, and with the most perfect 

 success, — as the experiments at Hatcham have abundantly 

 shown, — is not only to be congratulated, but is entitled to the 

 warmest thanks of the whole railway body politic. — Engineering. 



DURABILITY OF ENGLISH LOCOMOTIVES. 



The life of a locomotive boiler has been found to be about 

 350,000 train miles ; but this may probably on some lines go up 

 to 400,000, or even 500,000 miles, as its wear and tear would 

 depend greatly on local circumstances, and particularly on the 

 chemical qualities of the water employed. Assuming that the 

 life of the engine is determined by the endurance of the boiler, 

 and that if, under favorable circumstances, it will last 500,000 

 miles, then during that time the fire-box will i^robably require 

 to be renewed at least 3 times ; the tires of the wheels, 5 or per- 

 haps 6 times ; the crank-axles, 3 or 4 times ; and the tubes prob- 

 ably from 7 to 10 times. — Van Nostrand''s Engineering Magazine^ 

 Sept., 1869. 



PEAT FOR LOCOMOTIVE FUEL. 



The State-Line Bavarian Railway has been worked with turf 

 since 1847, or for above 20 years, rather from necessity than 

 choice. The peat is got from the bogs of Ilaspelmoos. The 

 method of its preparation is that of INI. Exeter, whose statement 

 is that he can produce 10,000 cubic metres of prepared turf per 

 annum, at a cost of 2.80 francs per metre. The turf, as dug or 



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