132 ELECTRICAL ADVANCE IN THE PAST TEN YEARS. 



In the large work of to-day the general practice is to build the dynamo 

 directly upon the shaft of the engine which drives it or upon the water- 

 wheel shaft, as the case may be. This avoids loss in belts or other forms 

 of gearing. 



Indeed, these large machines for producing electricity from i^ower 

 have in late years reached a perfection far beyond that of the steam 

 engine itself. The steam engine, in fact, has been forced to a higher 

 development in response to the demands of the electrical engineer. 



No service demanded of electricity has taxed the resources of elec- 

 trical and mechanical engineering so much as that of railway work. 

 The electric motors must work under the most varied conditions, stand 

 the hardest service, and run in the presence of water, slush, mud, and 

 dirt. They must run at all speeds, and be, so to speak, mechanically 

 and electrically.invulnerable. 



In the same way the engines and dynamos, together with other 

 parts of the system, must be of the most robust character. Inventive 

 and engineering talent was required to provide for the new and urgent 

 conditions. In the early days of electric-railway work the prospect 

 was not always bright or promising; and one of the chief setbacks 

 was the enormous wear and tear of certain parts of the machinery — 

 chiefly those known as commutators. This difficulty was solved by the 

 invention and application of carbon blocks in i)lace of metal " brushes" 

 used with the offending commutators. The "carbon brush " thence- 

 forth became almost as essential to the railway-motor machinery as the 

 carbon stick is to an arc lamp and did more than anything else to 

 change the prospect of failure into inevitable success. These technical 

 matters make a long story which would be out of place here. They 

 are merely alluded to for the purpose of emphasizing the fact that pio- 

 neer work in these advance movements has not been without its trials 

 and that a glimpse behind the scenes might have disclosed at times a 

 none too rosy aspect. 



In spite of the dififlculties to be overcome, the electric railway has, 

 in a very few years, put an end to horse traction on city railways, the 

 cruelties of which — not always to be avoided, perhaps — remain now 

 only as a fading memory. Electric traction has given greater speed, 

 better cars, which are lighted and heated electrically, and a resulting 

 cleanliness and comfort not otherwise attainable. 



But facts so evident call for no comment. Meanwhile it has been 

 shown that siiiglecars may be propelled at high train speeds with com- 

 parative safety. Even 60 miles an hour has been exceeded. It has 

 also been proved, by the construction of several huge electric locomo- 

 tives for the Baltimore and Ohio Eailroad, expressly for tunnel service, 

 that such electric machinery can haul the heaviest train loads and can 

 more than equal in power locomotives worked by steam. 



Electric traction is now generally regarded as the ideal method for 

 elevated railways and as practically indispensable to underground or 



