Gulf, Mobile & Northern / Mobile & Ohio / New Orleans, Mobile & Chicago 4-6-2 "Pacific" Locomotives of the USA

Locomotive number 425 was built by the Baldwin Locomotive works in Eddystone, PA on Jan. 16, 1928 for the GM&N and classified as a G-1 Pacific. When GM&O took over the GM&N, 425 was renumbered 580 (426 was renumbered 582). Both of these locomotives were sold to Paulsen Spence (Paulsen also owned the W&W's #98 and a number of other locomotives). Paulsen operated the 425 on his Comite Southern and Louisiana Eastern Railroads.

425 was later sold to Malcom Ottinger of Phoenixville, PA to be used on the Valley Forge S. Railroad in Kimberton, PA. In 1980 425 was stored at the Wilmington & Western Railroad in Delaware with some of Malcom's other railroad equipment. Malcom later sold part ownership of the 425 to another W&W member. It was steamed up once but lacked the proper paperwork on the boiler that was required in order for it to operate.

In 1984 425 was sold to Andy J. Muller Jr. of the Blue Mountain & Reading for $125,000. 425 is now at Port Clinton, PA as part of the RBMN RR Co. In 2002 she was in the Car Shop being restored for the B&O Birthday Party in 2003.

Class Details by Steve Llanso of Sweat House Media

Class 250 (Locobase 13889)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 40, pp. 298-305. Works numbers were 37746-37749 in May 1912.

The specs for this quartet state that the details are to be taken from the Southern Railway's specification E-50 for its set (Locobase 166) and the TT-50 spec for the tender. The superheater dimensions in the Baldwin sheet are given from the steam side of each element. This gave a lower numbervalue (660 sq ft) than the figure given in the Locobase data, which reflects usual Anglo-American practice in calculating surface area from the fire side of the tubes.

After almost 3 decades on the M & O, the class was scrapped in 1939-1940, just before the & O merged with the Gulf, Mobile & Northern to form the Gulf, Mobile & Ohio.

Class 260 (Locobase 15200)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Vo 68, pp. 128+ and Vol 75, pp. 135+. Works numbers were 56914-56916 in August 1923, 57657-57658 in April 1924, 58177 in January 1925, 59085-59086 and 59091-59092 in March 1926.

These large, handsome Pacifics were the elite passenger power on the M&O. They had good superheating proportions, direct heating surface supplemented by 48 sq ft (4.45 sq m) of combustion chamber and 27 sq ft (2.5 sq m) of arch tubes, and big 14" (356 mm) piston valves.

Class 40 / K-6 (Locobase 2789)

Data from L & N 8-1927 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also DeGolyer, Volume 41, p. 110. Works numbers were 38351-38352 in September 1912, 38426-38427 in October.

Built with 13" piston valves and outside radial valve gear, this quartet was purchased by a predecessor to the Gulf, Mobile & Northern at the same time as a set of 2-8-2s. The class was delivered with a good proportion of superheated surface area

The NO, M & C grew out of the 1909 merger of the Gulf & Chicago and the Mobile, Jackson & Kansas. It would be reorganized as the GM&N on 1 January 1917.

In 1921, the GM&N sold these engines to the Louisville & Nashville (L&N) .

The quartet operated as K-6s #296-299 on the L & N until 1950-1951

Class 425 (Locobase 1315)

Data from 1928 GM&N Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection, supplemented by DeGolyer, Vol 77, pp. 626+. Works numbers were 60339-60340 in January 1928.

Two built for the GM&N, which was later combined with the Mobile & Ohio as the GM&O. They were fitted with 12" (305 mm) piston valves and had 24 sq ft (2.2 sq m) of arch tubes contributing to direct heating surface area. #425's history extends for decades. After the merger, she was renumbered 580.

She went to the Lousiana Eastern in 1950. In the early 1980s, she was stored at the Wilmington & Western in Marshallton, DE, but never operated on those tracks because of her high axle loading. She then was moved to the Blue Mountain & Reading where she went into tourist service.

Idle for a dozen years, during which the BM&R went out of business to be succeeded by the Reading, Blue Mountain & Northern, the 425 was restored to operating condition in 2008.

Specifications by Steve Llanso of Sweat House Media
Class25026040 / K-6425
Locobase ID13,889 15,200 2789 1315
RailroadMobile & Ohio (GM&O)Mobile & Ohio (GM&O)New Orleans, Mobile & Chicago (GM&O)Gulf, Mobile & Northern (GM&O)
Number in Class41042
Road Numbers250-253260-26940-43 / 296-299425-426 / 580-581
Number Built41042
Valve GearWalschaertBakerWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)12.50131212.17
Engine Wheelbase (ft)31.3734.9231.3333.08
Ratio of driving wheelbase to overall engine wheebase 0.40 0.37 0.38 0.37
Overall Wheelbase (engine & tender) (ft)67.0470.7562.8365.79
Axle Loading (Maximum Weight per Axle) (lbs)48,30044,00043,000
Weight on Drivers (lbs)141,500162,000123,000129,000
Engine Weight (lbs)232,000277,000198,000213,000
Tender Loaded Weight (lbs)152,000194,000152,400182,000
Total Engine and Tender Weight (lbs)384,000471,000350,400395,000
Tender Water Capacity (gals)750010,00070008500
Tender Fuel Capacity (oil/coal) (gals/tons)12161618
Minimum weight of rail (calculated) (lb/yd)79906872
Geometry Relating to Tractive Effort
Driver Diameter (in)72.50736969
Boiler Pressure (psi)185200185210
High Pressure Cylinders (dia x stroke) (in)24" x 28"25" x 28"22" x 28"22" x 28"
Tractive Effort (lbs)34,98140,75330,88535,058
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.05 3.98 3.98 3.68
Heating Ability
Firebox Area (sq ft)192299180196
Grate Area (sq ft)5466.7046.8054.20
Evaporative Heating Surface (sq ft)3058334124802697
Superheating Surface (sq ft)806794550620
Combined Heating Surface (sq ft)3864413530303317
Evaporative Heating Surface/Cylinder Volume208.58210.02201.31218.93
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation999013,340865811,382
Same as above plus superheater percentage12,08815,87510,21613,545
Same as above but substitute firebox area for grate area42,97971,16239,29448,980
Power L117,18718,32814,38618,147
Power MT803.34748.26773.55930.40


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