1843.] 



THE CIVIL ENGINEIjR AND ARCHITECT'S JOURNAL. 



241 



span, with a radius of 72 feet, and three arches of 20 feet span each at 

 either end, forming the abutments. The main pier is founded upon rock, 

 24 feet heneath the bed of the river ; and the height from the foundation to 

 the top of the parapet is l. r iG feet 6 inches ; the under side of the main arch, 

 at the crown, is thus 121 feet 9 inches above the level of the sea. 



The paper describes at length the nature of the building materials em- 

 ployed, the dressing of the stones, the composition of the mortar, the ge- 

 neral detail and dimensions of the construction, the centering of the arches, 

 with the precautions used in striking them, and gives a very full account of 

 the travelling and other cranes employed in the construction ; these are 

 stated to have been very efficient. The north arch, of 100 feet span, con- 

 taining about 980 tons of stone, was entirely turned with two of the cranes, 

 in 28 hours, giving an average weight of 1 7 -J tons of stone laid by each 

 crane per hour. 



The perseverance and practical skill of Messrs. Gibb, of Aberdeen, the 

 contractors, are particularly mentioned, as the difficulties attending the get- 

 ting down the foundations, especially that of the main pier, were very great, 

 and required all their talent and energy. The detail is given of the precau- 

 tions taken with the coffer-dam, in which at one period a steam-engine of 

 20 h.p., working two pumps of 18 inches diameter each, was insufficient to 

 keep down the water, and it became necessary to drive a range of sheet 

 piling all round withinside the dam, before the leakage through the bad 

 strata above the rock could be stopped. 



By calculation it appears, that the pressure on the foundations of the 

 highest pier in the bridge is about 37 tons on each square foot, exclusive of 

 the additional weight of the passing coal-trains, which frequently weigh 120 

 tons each. 



The bridge was commenced on the 17th of March, 1836, and was finished 

 on the 28th of June, 1838, occupying about 714 working days, and cost, 

 with the extra works, nearly £40,000. 



The paper is illustrated by three drawings, showing a plan and elevation 

 of the bridge in several stages of its construction, and when completed ; 

 the details of the centres, hoists, and cranes, the coffer-dam, engine, pumps, 

 and of the foundations of the whole structure. 



Mr. Vignoles had examined the bridge very minutely, and had been much 

 struck with the excellence of the workmanship, which was quite in accor- 

 dance with the beauty and simplicity of the original design ; it was an ex- 

 traordinary example of care and attention on the part of the contractors, 

 and did infinite credit to all engaged in it ; yet with all this, it had cost less, 

 in proportion to its dimensions, than any similar structure in this country. 



The President observed, that the structure first proposed was to have been 

 of cast iron, but when be and his partner, Mr. Burges, were consulted, they 

 advised the employment of the freestone from the adjoining quarries, on 

 Lord Londonderry's estate, and they furnished a design, based upon that of 

 Trajan's bridge, at Alcantara, which was adopted by the directors ; but sub- 

 sequently an alteration was made, by introducing three small arches in each 

 abutment, which, in his opinion, had injured the design ; that was the ex- 

 tent of his connexion with the bridge ; the merit of the construction must 

 be given to the engineer and the contractors, and he must corroborate the 

 statement of the superior manner in which the work had been executed. 

 The bridge had been placed nearly at the spot marked out by Mr. Telford, 

 for the Great North Road to cross the Wear, and as the railway would now 

 form part of the line between Newcastle and Darlington, Mr. Telford's plan 

 would be virtually executed, although with the difference of substituting a 

 railway for a turnpike road. 



" Description of the American engine ' Philadelphia,' made by Mr. Norris 

 of Philadelphia, North America, for the Birmingham and Gloucester Rail- 

 way." By G. D. Bishopp ; communicated by Captain W. S. Moorsom, 

 Assoc. Inst. C. E. 



The engine described in the paper, was made in the year 1840, and has 

 been in regular work for upwards of two years as an assistant engine upon 

 the Lickey inclined plane, which rises at an angle of 1 in 37J, and is 2 miles 

 4 chains long. Its construction is what is termed a " bogie" engine, having 

 a four-wheeled truck, to support one end of the boiler, while the other end 

 rests upon the driving wheels. It has outside cylinders, inclined so as to 

 clear the bogie wheels, over which they are placed, and it has inside 

 framing. 



The boiler is cylindrical, 9 feet long and 3 feet 4 inches diameter, of 

 plates |-inch thick. The fire-box attached to it has three of its sides square, 

 and the front semicircular, with a spherical dome on the top, and the area of 

 the fire-grate about 10 square feet j it was originally constructed of iron, 

 with water spaces 2\ inches wide, the crown being supported by stay bars in 

 the usual manner; but it was destroyed in about eight months, and has been 

 replaced by a copper fire-box, of plates f-inch thick, with a tube plate f-iuch 

 in thickness. The tubes are 94 in number, 8 feet 11 inches long, and 2 

 inches diameter outside ; they were originally of copper, but were replaced 

 by brass tubes when the new fire-box was fixed. Midway between the two 

 end plates, is a third plate through which the tubes pass, so as to serve as a 

 support, and to prevent them from sinking in the middle. The total internal 

 area of the tubes is 404 square feet. The chimney is 13} inches diameter 

 internally, by 13 feet 10 inches high from the rails, and has not any damper. 

 The framing is entirely of wrought iron, with the axle guides, &c, forged 

 upon it. The " bogie " frame is also of wrought iron ; it is attached to the 



smoke-box by a centre pin, and is carried by two pair of wheels, 2 feet 

 G inches diameter, made of cast iron, chilled, and without tires. The dri- 

 ving wheels are 4 feet diameter, also of cast iron, but with wrought iron 

 tires ; they are firmly fixed upon a straight axle, as the cylinders are outside. 

 The cylinders are 12} inches diameter inside, with a length of stroke of 20 

 inches. 



Minute dimensions are given of the steam passage and valves (the " lead " 

 of which is J -inch, and to the eduction pipe nearly 4 -inch, the motion of the 

 slide extending l^-inch on either side of the centre line) ; the steam 

 chests, the regulator, the gearing, and feed-pumps, and all the other parts of 

 the engine aud connexions. 



The general summary of the work done (the details of which are in the 

 archives of the Institution of Civil Engineers) ■ shows that with a maximum 

 load of 8 wagons and 20 men, making a weight of 53} tons behind the 

 tender, the engine ascended the Lickey iuclincd plane at a speed of be- 

 tween 8 and 9 miles per hour. That with 6 wagons, or 39 1 tons, the 

 speed was between 10 and 11 miles per hour; that with 5 wagons, or 33 

 tons, the speed increased to between 12 and 15 miles per hour, and that in 

 assisting the ordinary trains, with 7 passenger carriages, the usual speed 

 has been 13£ miles per hour. There are three engines of this class kept at 

 the Lickey inclined plane for assisting the trains in their ascent, but one is 

 generally found sufficient for the daily service. 



The communication is illustrated by seven drawings of the engine and its 

 details of construction, which have been communicated through Captain W. 

 S. Moorsom, Assoc. Inst. C. E. 



Captain Moorsom, in answer to questions from members, explained that — 



Miles. Chains. 

 The length of the Lickey incline, rising 1 in 37-^, was 2 4 



The bank engine ran out from its house at the foot of 



the incline, at each trip, for a length of 14 



And continued running at the head of the train after 

 surmounting the incline, for about 23 



Thus giving an actual length on the ascent of ... 2 41 



And as the same distance was covered in returning, the length of each trip, 

 was rather more than 5 miles. This was exclusive of some occasional pi- 

 loting and train trips, which were, however, included in the general state- 

 ment of expenses. 



The account of the entire expense of the bank engine establishment was 

 made up of — 1°, The wages of the drivers and firemen ; 2°, Cost of coke, 

 oil and tallow ; 3°, Repairs, including wages and materials ; 4°, Depreciation 

 of stock, stated at the end of each half-year; 5°, General charges, com- 

 prising wages of pumpers, cokemen, cleaners and labourers ; cost of fire- 

 wood, hose-pipes, cotton waste, and all other stores ; salaries of superin- 

 tendents, clerks, foremen, time-keepers, and store-keepers; and the premium 

 paid to the men for saving the coke. 



The cost of working the incline plane was therefore, for each half-year 

 ending — 



The engines have been improved by the alterations made since their ar- 

 rival in England. These changes chiefly consisted in suppressing the tender, 

 and placing the receptacle for water and coke upon the boiler of the engine, 

 and in using the waste steam to heat the water; these had increased the 

 efficiency of the machine, and caused a considerable economy of fuel. All 

 the other changes were of minor importance, and had been chiefly suggested 



1 " Account of a Scries of Experiments on Locmnoiive Engines, &c," by 

 Capt, Moorsom, with Supplement, read April 7, 1840. Minutes of Proceed- 

 ings, page 45. 



2 'its, per ton, 3 *26s. W. per ton. « 25s, lljrf, per ton. 



