1855.] 



ON THE DUKABILITY OF KAILROAD lEON. 



239 



stationary steam power acting through di'ums and chains, at an aver- 

 age speed of 6 miles an hour. 



These rails have been in use thirteen years, and appear but very 

 little the worse for the traffic which has passed over them. This has 

 amounted to a gross weight of 7,840,000 tons, or 3,920,000 tons over 

 each track. Their duration may be fairly estimated at twice this 

 weight, or 7,8i0,000 tons over each track of rails. 



Case 8. — Railroads for the conveyance of goods, metals, and min- 

 erals, consisting of a single track of rails of the bi'idge pattern, weigh- 

 ing 75 pounds per yard, 2. .5 inches high, 2 inches wide at head, and 6 

 inches at base, laid in shallow cast iron chairs, which are spiked to 

 sleepers 9 inches wide, by 7 feet long, placed at tUstances of 3.5 feet 

 ap.art. 



The wagons travelling over this roud are of various patterns, and 

 are, with a few exceptions, devoid of springs. — Their weight, when 

 empty, varies from 26 to 03 cwts., and when loaded, from to 11 tons. 

 The speed at which they are drawn varies, also, from 3 miles an hour, 

 the speed of those drawn by horses, to 12 miles an hour, for those 

 drawn by steam locomotive engines. 



These rails have had the wear and tear from the passage of 4, 783,000 

 tonsof miscellaneous traffic, but from their damaged condition, we cannot 

 estimate their duration at more than 5,500,000 tons. 



C.iSE 9. — Railroad for the conveyance of coal, consisting of a single 

 track of parallel rails, weighing 40 pounds per yard, 3.87 inches high, 

 1.87 inches wide at the head, 1.2 inches wide at base, with centre web 

 .56 inch thick, laid in cast iron chairs pegged to stone blocks, weighing 

 from 4 to 6 cwts. each, and placed at an average distance of 3 feet 

 apart from centre to centre. 



The wagons running on this road are drawn by horses at an average 

 speed of 4 miles per hour, and are mounted on four cast iron wheels, 

 28 inches in diameter, turning loosely on their axles, which are bolted 

 to the wrought iron frame of the wagon. They weigh, when empty, 3 

 tons, and when loaded, 5 tons 17 cwts. 



The gross traffic over this line has amounted, during the 1-3 years 

 which it has been open, to 8,626,000 tons, and it now remains inagood 

 working condition. The duration of these rails may, therefore, be 

 estimated at about 15,000,000 tons. 



Case 10. — Taff Vale P^ailroad, for the conveyance of passengers, 

 metals, minerals and general merchandize, between Cardiff and Merthyr 

 Tydfil. Upper section consisting of a single track of parallel rails of 

 a single head form, weighing 50 pounds per yard, 4.5 inches high, 2.2 

 inches wide at head, 2 inches width of lower web, and .66 inch thick- 

 ness of centre rib or web, supported at intervals of 3 feet by chairs 

 bolted to cross sleepers 10 inches wide by 9 feet long. The ballasting 

 under the sleepers consists of a thick stratum of broken cinders. 



The wagons and carriages running on this road, vary considerably 

 in their weight — from 2 tons 10 cwts. to 4 tons 10 cwts, when light, 

 and from 8 tons to 12 tons when loaded. They are furnished with 

 wrought iron wheels and tyres, bearing springs and iViction brakes, 

 and the p.asseuger carriages have buffer and draw springs. The loco- 

 motive engines employed, weigh about 20 tons, exclusive of tenders 

 and work at speeds varying from 15 miles per hour, for slow mineral 

 trains, to 30 miles an hour for passengers. 



These rails have been in use nearly 13 years, and from the most 

 careful computations, the traffic over them has been 5,400,000 tons. 

 At the crossing and portions of the line where a considerable braking 

 power is applied, their depth is reduced by abrasion, to 4.4 inches, but 

 in all other respects these rails are gencrall}' sound. Their duration 

 may be estimated as equal to the rolling of 10,000,000 tons. 



Case 11. — Tatf Vale Railroad— the down-line from the Aberdare 

 junction to Cardiff. Length of the lino, 14 miles, and falls at the rate 

 of 15 feet per mile. Rails of the parallel double headed section ; depth, 

 5 inches; width of head and foot, 2.5 inches; centre web, .75 inch 

 thick; weight, 72 lbs. per yard. They are supported at intervals of 2 

 i'eet 9 inches by cast iron chairs firmly bolted to cross sleepers, 10 

 inches wide by 9 feet long. In all other respects, the formation of this 

 road is similar to that of the upper section near Jlerhyr Tydfil. 



The cai'riages and engines last described, work on this section also, 

 and at similar speeds. It is traversed daily by 3 passenger, 1 mail, 

 and numerous luggage, metal, mineral and merchandize trains. The 

 passenger trains average about 96 tons gross each, but the mineral and 

 otlier trains sometimes e.Kceed 1000 tons in weight. 



From the annual traffic returns of this company, we find that in the 

 eight years that these rails have been laid, the gross traffic which has 

 rolled over them, amounts to 20,510,000 tons. Altlunigli this weight 

 has caused considerable lamination and abrasion ut the stations aud 

 on the sharpest curves, those rails are now in fair working order, and 



with attention to the sleepers and ballastiag, they will last for the con- 

 veyance of as much more. Hence their duration may be estimated as 

 equal to the rolling of 41,000,000 tons. 



Case 12. — Taff Vale Railroad — the up-line from the shipping port 

 of Cardiff to the Aberdare junction. This line is of the same length, 

 and is similar in its construction to the down line, with which it runs 

 parallel throughout. It is traversed, also, by the same engines and 

 and carriages, but the coal and coke wagons pass over this line empty. 



The rails are of the same date as those of the down line, aud the gross 

 weight which has rolled over them, amounts to 11,200,000 tons. Their 

 general condition is very similar to those in the down line ; and their du- 

 ration may be estimated as equal to the passage of an additional weight 

 of 11,200,000 tons, or a gross total of 22,400,000 tons. The greater 

 weight traversing the down line, is owing to the large quantities of 

 coal sent down for shipment ; the wagons used in the conveyance of 

 of which return empty over the up line to the collieries. 



The rails on both sections having suffered nearly alike in lamination 

 and abrasion, although one has sustained little more than half the 

 rolling of the other, is accounted for by the cicurastance of the gradient 

 being just sufficient to enable the engines and loaded wagons to roll 

 down the one line, while on the other the ascent with 90 or 100 empty 

 wagons is accomplished with difficulty by engines having 18 inch 

 cylinders. The abrasion and injury to the rails by the slipping of the 

 engine wheels in ascending gradients, is probably equal to, if it does 

 not exceed, that from the rolling of the traffic. 



Case 1-3. — Railroad for the conveyance of minerals to the Hirwain 

 Iron Works, consisting of a single track, 3 miles long, of the 4 feet 8.5 

 inch guage. Rails, of a parallel single head form, 4.25 inches deep, 2.5 

 inches wide at the head and .75 inch thickness of centre web. They 

 weigh 46 lbs. per yard, and are screwed fast to single cheek chairs on 

 massive stone blocks every 4 feet. The ballasting consists of blast 

 furnace cinders, and dust from the coke yard. 



The carriages are constructed of wrought and cast iron frames, and 

 are mounted ou 4 cast iron wheels 32 inches diameter, turning loosely 

 on axles bolted firmly to the carriage frame. They weigh when light 

 2 tons 5 cwts., and when loaded, 5 tons, but are unprovided with any 

 springs. The locomotive engines weigh 10 tons each wdien in running 

 order aud propel the loaded carriages at an average speed of 10 miles 

 an hour. 



This road has been laid with these rails about 4 years. — The gross 

 weight which has passed over it in that time amounts to 1,055,000 tons. 

 Ou carefully examining the state of the rails after this traffic, 23 per 

 cent, were found laminated to an extent rendering their immediate 

 replacement by sound rails indispensable ; while the others cannot, 

 under existing circumstances, last more than 2 years again. The dura- 

 tion, then, of the rails on this road may be estimated as equal to the 

 passage of 1,318,000 tons, or considerably less than cither of the 

 previous examples. 



In reference to the foregoing examples of the duration of railway 

 bars under different conditions of laying and working, we may remark 

 that in every instance where, in the construction of the. permanent way, 

 sufficient solidity has not been obtained by the employment of adequate 

 sleepers, the destruction of the rails has been most rapid. This was 

 the result with cases 1 and 6, and the effects are visible in 3, 4, 5, and 

 8. The greater duration of 11 and 12 over the others, must be ascribed 

 to the use of heavy rails, wagons and carriages with bearing springs, 

 and a well constructed and carefully maintained permanent way. No. 

 12 is a very favorable instance of durability — probably, equal to any 

 ever laid, which has principally resulted from the very favorable grade 

 of the line. Xo. 10, with heavier rails, would have equalled No. 1], 

 as the conditions are otherwise similar. — The absence of bearing springs 

 to all wagons, except those iu cases 10, 11 and 12, must also li.avc Imd 

 a very prejudical cifect on the r.ails and greatly lessened their dura- 

 tion. — In case 6 the rails were too weak, and the support vmequal to 

 the heavy wagons emploj-ed. Case 9, with heavier blocks and lighter 

 wagons, is a very favorable specimen of a mineral railroad. Ca.se 13 

 .shows tlie most unfavorable results of the whole number detailed, but 

 when tlie very inferior quality of the metal used and the defective 

 nature of the fastening employed is fully considered, a dilfcrcnt result 

 could scarcely be expected. 



In the tabular statement of the <luration of the rails, it is supposed 

 that the cost of labor and materials in replacing unsound bars and the 

 ultimate expenses incidental to the entire renewal of tlie rails, when 

 worn out, will be equivalent to the value of the old metal obtained. 

 This is found to agree very nearly with the results obtained in practice. 



We have in our possession, similar notes respecting the duration of 

 cast iron rails, of which numerous example niny bo seen at or in the 



