"The whole rise in the 550 feet is 3 feet, or 1 in 155. "The gravity of one ton upon the lower length is, therefore, 2,240 lbs. divided by 250, or nearly 9 lbs. Upon the upper length it is 2,240 lbs. divided by 116, or 19 lbs., and the average of gravity upon the whole length is 2,240 divided by 155, or 141⁄2 lbs. 66 Experiment 1st. The general average resistance of four tons gross (viz. waggon 1 ton 16 cwt. and goods 2 tons 4 cwt.), as ascertained by your chairman (C. H. Turner, Esq.) and Mr. Colville, by means of a spring weighing machine, was 127 lbs. ; from which, if we deduct the gravity of 4 tons, or 19 lbs. multiplied by 4, say 77 lbs., there is left, for the friction of 4 tons, 50 lbs., which gives for the friction of 1 ton 12lbs., th of the whole weight moved. "This friction is not more than upon the best constructed edge railway. I consider that the greater size of our wheels, and there being no flanche, compensate for the roughness of the stones (from their being newly laid,) as compared with an iron railway.* 66 Experiment 2d. A pony 12 hands high, weight 4 cwt., drew upon the upper part in your presence, and afterwards upon the lower part in your and the directors' presence, six tons (gross). I was not aware that the difference of inclination of the two parts was so great, or he should have * In consequence of the improved mode of laying rails, the resistance from friction is now about 8 lbs. gone over the upper length again, he had done it more than once before. "Taking, therefore, the upper part on the rise of 1 in 116, the pony's exertion was, Gravity 193 lbs. multiplied by 6, or Making together lbs. - 116 - 75 191 and 191 lbs. divided by 12 lbs. (the friction of one ton) gives 15 tons. "The pony's work, therefore, was equal to fifteen tons drawn upon a level road. "Experiment 3d. The waggon, loaded as in the preceding experiment, being turned round and started by the pony's exertion, ran down the whole length to the Dock-gate with increasing velocity (the pony not drawing it), and for a distance off the tramway, before it could be stopped; consequently the average fall of 1 in 155 exceeded the resistance by friction. Experiment 4th. A powerful horse (weight 14 cwt.) drew 12 tons gross (the waggon and truck loaded) from the West India Dock-gate to the turnpike at the rate of 4 miles per hour. "Taking then the upper length, or a rise of 1 in 116, we have, Gravity 12 times 193 lbs., or Friction 12 times 12 lbs., or Making together lbs. 232 150 382 and 382 lbs. divided by 12 lbs. gives 30 tons. "The horse's work was therefore the same as if he had been drawing 30 tons upon the level. "The full average work of a horse per day is 150 lbs. moved 20 miles; consequently the pony was exerting one fourth more than the average work of one horse through the day; and the horse was doing the work of 24 horses. "The horse appeared to go easily; but the exertion was, of course, too great to be continued for any considerable time, so as to form a basis for general calculation. 66 Upon the whole, I think the conclusion is, that if the road were level, the work of a London draught horse upon the tramway would be ten tons (gross); but as the Commercial Road rises towards London, a deduction must be made from this for gravity, the amount of which depends upon the inclination of the road, and is common to all kinds of roads and railways. Therefore, taking all things into consideration, I am of opinion that six tons (gross) from the Docks to Whitechapel, and a greater weight from Whitechapel to the Docks, may be considered a proper load for one horse on the tramway." The following is the specification for making a road with granite blocks on each side of the Geese Bridge Valley, on the Holyhead Road : "On the steep parts of the road, as shown on the section from the letter A to the letter B (on the east side of the valley, and from C to D on the west side), two lines of stone blocks are to be laid down, to form a tram or track for the wheels of carriages. These blocks are to be of granite, from the quarries at Mount Sorrel. They are to be twelve inches deep, fourteen In proportion as roads or streets are paved with proper skill and care, the advantages in diminishing inches broad, and not less than four feet long. They are to be pricked on each face, the upper surface to be parallel to the bed, and the sides and ends dressed square, and pricked in the same manner as the specimen now lying at Snow Hill Wharf, near Weedon, for the inspection of those who may propose for the work. The foundation for these blocks is to be prepared in the following manner, as shown in plan 3.:-The ground is to be excavated to the proper depth, to receive the different materials hereafter described, so that the upper surface of the stone blocks will be on a level with the carriage-way when finished. The width of this opening is to be eight feet, extending from the channel towards the centre of the road. When the bottom is properly and evenly levelled, a pavement of limestone, or good sandstone, from the quarries near Stow, is to be laid by hand in a similar manner to that described for the road-work. These stones are to be eight inches deep throughout, to be firmly packed, and perfectly level from side to side. When the interstices are filled up with stone chips, and the whole firmly packed, good lime grout is to be poured into the joints. One barrel of lime and two barrels of sand and gravel, properly mixed, and used whilst fresh, are to be used on every lineal yard. This work is to be done to the satisfaction of the engineer, and every care taken to render it solid and substantial in every respect. On this pavement three inches of broken stone from Lovel's or Stow quarries are to be laid: no stone is to exceed one inch and a half in its largest dimensions. They are to be put on after the foundation course has been inspected and approved by the engineer, and not before. On this layer of stone two inches of the best gravel is to be laid it is to be rolled with a metal roller several times, so as to consolidate the stone and gravel together, and render it one firm mass. On this gravel the stone blocks or trams are to be laid: they must be even on the bed, and the ends must abut together, and form one continuous and uniform line. The surface of each must be on the same level, and perfectly uniform with the blocks : the tractive force required for drawing carriages upon them will be augmented. On a smooth, on the opposite side; that is to say, the surface of each line must be perfectly level, and correspond throughout. When the trams or blocks are laid to the satisfaction of the engineer, the space below them and the space on the outside is to be filled up to within six inches of the upper surface with broken limestone, no piece of which shall exceed one inch and a half in its largest dimensions. A row of paving-stones of granite, not less than six inches deep, five inches wide, and nine inches long, is to be placed on each side of the trams or blocks: these stones to be of the best granite from Mount Sorrel quarries. They are to be dressed in the same manner as the stones called sovereigns in the London market. These paving-stones are to be placed close to each side of the blocks, and firmly packed up with Hartshill stone, broken not to exceed two inches in its largest dimensions for the first three inches; the next three inches towards the surface to be broken to one inch and a half in its largest dimensions. When this work is completed, the whole is to have a top dressing of one inch of good gravel, evenly spread, and rolled twice in wet weather. The sides of the road next the trams is to be formed and dressed so as to come on the same level, and when the whole is finished to form one uniform surface of carriage-way, as shown on the plan. “A drain, eight inches deep and four inches wide, is to be formed on each side of the trams, the bottom of which is to be eight inches below the bottom course of the pavement, and is to be formed of rubble-stone or bricks, so as to lead off any under or surface water that might otherwise injure the foundation or bed of the trams. These drains are to have off-lets into the large side drains, which are to be two feet under the surface of the road-way where the trams are to be used; and, should it be thought necessary, wells or upright shafts must be constructed at every 100 yards apart through the cuttings, to let the surface water into the under drains, without running along the surface. The tops of these wells are to have an iron grate one foot square, the bars of which are to be two inches deep, one inch and a half apart, and one inch wide, set in proper frames." -See Appendix, No. III. on Tramways. |