CHAPTER VI. 



Comparative Weights of some Types of Modern Locomotives. 



Weights of Locomotive Engines. The demand for higher speeds 

 of passenger trains, with more conveniences, luxuries, and con- 

 sequent increased weights in the carriages, has naturally led to 

 greatly increased power and weight of the locomotives devoted 

 to the passenger service. Although these engine weights have 

 so largely increased during the past twenty-five years, there is 

 nothing to indicate that they have yet reached the maximum. 

 The tendency is still to increase, and will doubtless continue, so 

 long as the permanent way can be made to sustain such enormous 

 rolling loads. Locomotives for goods trains have also increased 

 in power and size, but perhaps not in the same proportion as 

 those for the passenger service. There is not the same dis- 

 position to expedite the transit of goods and minerals, which do 

 not deteriorate during a long journey. Perishable articles, such 

 as fish, fruit, and milk, are usually conveyed by passenger trains, 

 or trains set apart specially for the purpose. 



The heavier engine doubtless possesses greater tractive 

 power, but apart from the question of tractive power is the all- 

 important one of steadiness and safety on the rails. A loco- 

 motive passing round a curve, even at a moderate velocity, 

 produces disturbances in proportion to the capability of the 

 machine to adapt itself to the altered position, and if both the 

 engine and permanent way are constructed so as to be almost 

 unyielding, then destructive wear and tear and increased risk of 

 derailment must ensue. The adoption of the four-wheel bogie 

 truck to the locomotives on our home and continental lines 

 although very slow in coming has contributed greatly to their 

 improvement, enabling the weight to be distributed over a 

 longer, yet more flexible wheel-base, affording greater facility 

 and comparative safety in traversing curves ; and rolling, or 



