Baltimore and Ohio class N-1

The Baltimore and Ohio Railroad's sole Class N-1 steam locomotive, #5600 George H. Emerson, was the first duplex locomotive and the first 4-4-4-4 locomotive ever built. It was designed and built by the railroad's own shops in 1937. The rear set of cylinders were placed beside the firebox. This allowed the locomotive's wheelbase to remain the same. The space beside the firebox was hot and dirty, which caused premature cylinder wear, and the placement of the cylinders limited the size of the firebox. These same problems occurred on the PRR Q1, which also placed the rear cylinders by the firebox. It was built by the B&O's own Mount Clare Shops in 1937 however it had problems with the sizes of the cylinders facing the other direction. In 1943 no . 5600 was retired from service. The locomotive was then Scrapped in 1950 .

• 
  B & O 5600 at the 1939 New York World's Fair
• 
  Detail, showing the rearward cylinders and gear

B&O #5600 George H. Emerson
Baltimore and Ohio Railroad #5600 George H. Emerson
Type and origin Power type Steam Builder B&O Mount Clare Shops Build date May 1937 Total produced 1
Specifications Configuration: ​  • Whyte 4-4-4-4  • UIC 2′BB2′ Gauge 4 ft 8 ^1⁄2 in (1,435 mm) standard gauge Leading dia. 36 in (914 mm) Driver dia. 76 in (1,930 mm) Trailing dia. 42 in (1,067 mm) Minimum curve 13° or 441.68 ft (134.62 m) normal, 18° or 319.62 ft (97.42 m) slow Length 117 ft 0 ^1⁄4 in (35.67 m) Adhesive weight 238,000 lb (108,000 kilograms; 108 metric tons) Loco weight 386,500 lb (175,300 kilograms; 175.3 metric tons) Tender weight 350,000 lb (160,000 kilograms; 160 metric tons) Total weight 736,500 lb (334,100 kilograms; 334.1 metric tons) Tender type Vanderbilt with two 3-axle trucks Fuel type Coal Fuel capacity 46,000 lb (21,000 kilograms; 21 metric tons) Water cap 22,000 US gal (83,000 l; 18,000 imp gal) Firebox:  • Firegrate area 80.5 sq ft (7.48 m^2) Boiler pressure 350 lbf/in^2 (2.41 MPa) Heating surface 4,897 sq ft (454.9 m^2)  • Tubes and flues 4,220 sq ft (392 m^2)  • Firebox 677 sq ft (62.9 m^2) Superheater: ​  • Type B&O  • Heating area 1,312 sq ft (121.9 m^2) Cylinders Four, duplex Cylinder size 18 in × 26.5 in (457 mm × 673 mm) Valve gear Walschaerts
Performance figures Power output 3,936 hp (2,935 kW) at cylinders Tractive effort 65,000 lbf (289.1 kN) Factor of adh. 3.66
Career Operators Baltimore and Ohio Railroad Class N-1 Numbers 5600 Official name George H. Emerson Retired 1943 Scrapped October 1950

References

• Reed, Brian (June 1972). Pennsylvania Duplexii. Loco Profile 24. Windsor, Berkshire: Profile Publications Limited. pp. 266–267.