322 



THE WORLD'S ADVANCE 



Two of the Earlier Atlantic Type Locomotives Used on the Pennsylvania Railroad. At the Left is 

 the First Locomotive of That Design, Which Was Later Replaced by the One at the Right for the 

 Reason That the Arrangement of Separate Cabs for Engineer and Fireman Was Found Impracticable. 



No. 5075, amounted to nothing more than 

 a big freight boiler on passenger wheels. 

 The scheme was an instant success. The 

 big boiler gave the engine tremendous 

 steaming capacity, while the passenger 

 style of wheel arrangement permitted it 

 to run smoothly at a high rate of speed. 

 This engine was tested on the road 

 and finally on the special testing machine 

 at Altoona, as shown in the third view. 

 Tests furnished data on horsepower, 

 speed and other factors, which enabled 

 the officials to arrive at accurate con- 

 clusion regarding the engine's capacity. 

 As a result of these tests the engine was 

 equipped with new and lighter cross- 

 heads of a special design, a new trailing 

 truck and a superheater. It was then re- 

 numbered 1067, as shown in the fifth 

 view. 



In the meantime another engine, No. 



1092, illustrated in the fourth view, had 

 been built with rotary valves. This was 

 done in a conscientious attempt to arrive 

 at the truth respecting various systems of 

 steam distribution. The engine was not 



a success, and 



had to be re- 



built, but 



it served the 



purpose of 



showing the 



deficiencies o f 



this form of 



construction. 

 The sixth 



picture repre- 

 sents one of 



the latest E- 



6-S e n g i n es. 



This class is 



very popular among engineers on account 



of its speed and power, and among repair 



inspectors because it never breaks down. 



The Third Atlantic Type Locomotive Used Was in Reality 



a Freight Engine Boiler Mounted on Passenger Engine 



Wheels. 



The officials are interested because the 

 engines of this class are remarkably eco- 

 nomical. 



While the foregoing-mentioned devel- 

 opment was in progress, the Pennsyl- 

 vania Railroad experimented with Prairie 

 and Pacific types of American-built loco- 

 motives and with an Atlantic engine im- 

 ported from France. Not one of these 

 types has been able to compete success- 

 fully with the E-6-S engines on the ordi- 

 nary divisions of the road. 



The traffic is very exacting, owing to 

 the crowded condition of the road and 

 the importance of the trains that must be 

 handled every day. High speed has been 

 a requirement for a number of years. 

 This will be understood when it is ex- 

 plained that the standard driving wheel 

 diameter for express engines has been 80 

 inches for more than twenty years on the 

 Pennsylvania Railroad. This dimension 

 was incorporated in all the locomotives 

 shown herewith. 



The object sought in designing the 

 latest class was a combination of speed 



and power. 

 This was 

 achieved, a I - 

 though every 

 expert knows 

 the difficulty of 

 attaining such 

 a desirable re- 

 sult. Some re- 

 m a r k a b 1 e 

 speed records 

 were made 

 years ago, but 

 the weight of 

 the trains involved was not great. The 

 old-time fast engine had what, for want 

 of a better term, may be called a genteel 



