1282
THEORY AND PRACTICE OF ENGINEERING.
Book II.
connected with two force-pumps by means of copper pipes and gun metal nozzles:upon the plungers of the four presses rest two additional frames, which are attachedto the one below by four sets of parallel motion bars, so that they rise trulv perpendicular."When it is required to move a carriage from one line of rails to another, the apparatusis pushed under it, and when the carriage is in a position directly over the frame, thelarge pump which acts upon the four hydraulic presses raises the frames until theyarrive under the axles of the carriage wheels; after this the smaller pump is worked,which raises the flanges of the wheels clear of the rails: when the carriage is moved, astopper is unscrewed, which permits the water to flow from the presses back again into thecistern, and the carriage is lowered to the rails ; the apparatus is then drawn out and readyto be again made use of; the cost of this machine is about 220/., and was designed by ArthurJohn Dodson.
Locomotive Engines on the London and Birmingham railway are all constructed withfour wheels and in one uniform pattern; the passengers’engines have 12-inch cylinders,and the pistons an 18-inch stroke; the driving wheels are in diameter 5 feet, and thecarrying wheels 4 feet: the engines employed for the transport of goods have 13-inchcylinders, and a stroke of 18 inches also, but in these all the wheels are 5 feet in diameter;a passenger engine with its coke and water in the fire-box and boiler weighs 9 tons 13 cwt.lqr., and the other 11 tons 13cwt. 1 qr.
The framing of these engines is fixed inside the wheels, which allows of its being betterattached to the boiler; the whole is of wrought-iron; the cylinders are also made fastto this frame by strong wrought-iron bars, as are the cranks and fore axles : when theengine is either advanced or made to retrograde, the motion is conveyed through theframing alone, and no strain whatever is produced upon other parts. There are twobearings inside the wheels alone on the axles; and the bushes in which the axles run areso fitted to the frame that the springs have a vertical movement and no lateral action ;they are so arranged with a flange at their sides, that if an axle were to break, they wouldsupport the engine for a time.
Two of these Engines , made by Edward Bury , in the year 1839, performed a journeyof 700,000 miles at the following cost: for the first six months the cost of conveyance ofpassengers was of a penny per ton per mile ; and for the second 6 months ; and forthe first six months of the other engine carrying goods, the total cost per ton per mile wasToaif a penny, and for the second six months of a penny : this calculation includedthe cost of coke, oil, tools, wages, repairs, and general charges.
Locomotive Engines., manufactured by Mr. Norris, of Philadelphia , and sent by him tothe Grand Junction Railway : the construction of these engines was simple; their hollerswere horizontal; each contained 78 2-inch copper tubes, 8 feet long each, with an ironfire-box : the cylinders were 10} inches in diameter, and were slightly inclined downwards,and the piston-rods were made to work outside the wheels, so that cranked axles were notrequired: six wheels supported the frame, and the two driving-wheels were 4 feet indiameter, placed close before the fire-box : the other four wheels were 30 inches indiameter, and attached to a truck, on which rested the front end of the boiler: thistruck, by means of a centre-pin, was connected with the frame, which was made to turnfreely, and with very little stress, along any curve in the rails.
The weight of one of these engines, when the boiler and fire-box were full, was 9 tons11} cwt.; that of the tender, with 21 cwt. of coke and 520 gallons of water, was 6 tons4} cwt. ; when empty it weighed only 8 tons : 62 pounds per square inch was thelimits of working pressure of the steam on the boiler, and when the engine passed aplane with a rise of 1 in 330, with a load of upwards of 100 tons, the speed varied from 14to 22 miles in an hour, and on a plane of 1 in 177, from 10 to 14 miles per hour. 'Therise of the gradients from Liverpool to Birmingham is 620 feet: and from Birmingham toLiverpool 380 feet, exclusive of those in the Liverpool and Manchester Railway . In sevenjourneys of 596 miles up to Birmingham , the engine conveyed 682 tons, evaporating12,705 gallons of water, and consuming 265} cwt. of coke: in seven journeys the otherway, or returning, the same engine conveyed 629 tons gross, evaporating 12,379 gallons ofwater, and consumed the same quantity of coke.
The price of these engines complete, including the duty, was about 1600/: they were sowell adapted to travel over a curved line, that they have gone at a speed of 20 milesper hour round one of 10 chains radius; when on a straight line they travelled often 40miles per hour, and appeared less likely to be thrown off the rails than the ordinary loco-motives.