EXPLANATION OF THE PLATES. 40? 



Duplicates of such of the parts as are liable to derangement are kept in readiness, 

 powerful cranes and hoisting girders are fixed, and the various tools so arranged that 

 the taking to pieces and refixing any part of the engine and pump can be effected 

 without loss of time. 



The engine is calculated to raise 2250 gallons of water per minute. 



PLATES LXXXIX. TO XCII. 



PATENT LOCOMOTIVE ENGINE, 



MADE BY MESSRS. R. STEPHENSON AND CO., NEWCASTLE-ON-TYNE, 

 FOR THE LONDON AND BIRMINGHAM RAILWAY. 



This engine was made in 1836 for Messrs. Cubitt, the contractors for constructing 

 a part of the London and Birmingham Railway near Berkhampstead, and was used 

 by them for carrying the earth excavated in the construction of the line. The engine 

 was employed in this manner for about a year and a half; when, the works being 

 nearly completed, it was no longer required, and was purchased by the Railway 

 Company for the purpose of carrying ballast for repairing the road, and other similar 

 purposes, in which work it is now employed together with other engines. 



Although the original cost of these engines is very considerable, being about l 400 

 each, it is found to be advantageous to use them in executing the earthwork of rail- 

 ways when the earth has to be carried to any considerable distance, as they take the 

 place of so many horses and greatly expedite the work. They are also generally 

 worth a great deal when done with for the particular purpose, as was the case with 

 this engine, which was sold for upwards of two thirds of its original cost. The 

 expense of using them is nearly the same as that of doing the same work by horses, 

 if the saving of time from the greater speed and heavier loads that can be carried are 

 not taken into the account ; but the advantage in these respects is so great that 

 locomotive engines are generally used for the works of railways whenever the earth- 

 work is of any considerable importance. 



A locomotive engine differs considerably from other steam engines in many 

 particulars, as the engine and boiler are combined together in one machine, and have 

 to be carried along at a great velocity, together with the fuel and water required 

 for supplying the boiler. Very considerable modifications in the construction are 

 thus rendered necessary, in order to obtain sufficient lightness and compactness 

 combined with the requisite power. The cylinders are very much smaller than is 

 usual in other engines, the steam used being of very high pressure ; the boiler is also 

 made of small dimensions in proportion to the power, for the sake of portability, 



