The Atlantic, or 4-4-2, type locomotive was developed in an 

 effort to retain the desirable features of the American, or 4-4-0, 

 type of locomotive and at the same time to produce a locomo- 

 tive in answer to the demand for greater power. To do this, the 

 firebox was increased in area by making it considerably wider, 

 so that a greater amount of soft coal could be burned. The diam- 

 eter of the barrel of the boiler was increased to allow for greater 

 heating surface, which, of course, increased the weight on the 

 drivers. 



To make room for the driving wheels without unduly increas- 

 ing the length of the tubes in the boiler, the driving wheels were 

 moved forward, the main driver being in the rear instead of in 

 front as in the American type locomotive. In order to carry the 

 weight of the firebox, which, with the new driving wheel loca- 

 tion, overhangs the rear driver too much to be properly sup- 

 ported, a two-wheel trailer truck was used. This trailer truck, 

 which is fulcrumed a short distance back of the main driver, is so 

 designed that it has lateral motion, and provision is made for ash 

 pan as well as firebox clearance. 



By the use of higher steam pressure, larger heating surface and 

 grate area, the use of passenger locomotives of the three-coupled 

 type, with the troubles incident to the use of long parallel rods, 

 was put off^for a decade. 



General Electric Locomotive, 1926 



A detailed and exquisitely made operable model of the 

 New^ York Central class T-3A electric locomotive No. 1 173, 

 now^ No. 273, was constructed by W. Howard R. Parsons, 

 and was donated by him in 1952 to the Museum (USNM 

 314237). 



The model (figure 75) is powered by eight electric motors, 

 as is the full sized original, one for each axle, but because of 

 space limitations and power requirements the model's drive 

 is through gears rather than direct. The model operates on 

 12-volt direct current. Its length is 43 inches and its gauge is 

 3^2 inches. 



The New York Central System purchased 10 class T-3A 

 locomotives in late 1926 at a cost of $100,000 each. These 

 supplemented an earlier group of 10 T-l's and 16 T-2's 

 built for the New York Central from 1913 to 1917 at the 

 Erie, Pa., plant of the General Electric Co. Of this total of 



94 



