30 Book of Locomotives 



" Experiments " (wheel formula 4-6-0). 

 At that formula the North-Western have 

 stopped though the newer engines are 

 much bigger than the " Experiments ". 



To follow up our brief sketch of the 

 development of the express engine, let us 

 now wing our way to the big rival of the 

 North- Western, the Great Northern. Here 

 we found Stirling's gallant single-wheeler 

 overpowered by the big increase in loads. 

 The Great Northern went straight from 

 the single-wheeler to the " Atlantic " (wheel 

 formula 4-4-2). For twenty years these 

 fine machines reigned supreme, now they 

 are giving place to what may easily prove 

 the final development of the steam loco- 

 motive before electricity takes charge of our 

 main lines. This is the " Pacific ' type, 

 which came out in 1922 on the Great 

 Northern, though in the ' Great Bear ", 

 on the Great Western, came the first example 

 built in Britain, in 1908. The wheel for- 

 mula of the " Pacific " type is 4-6-2. 



Already there are many running on the 

 London and North-Eastern of the Great 



