Great Northern Other Articulated Locomotives in the USA

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Class Details by Steve Llanso of Sweat House Media

Class M-2 - 1st batch (Locobase 352)

Data from GN 1916 Locomotive Diagram supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 34, pp. 45+ and "Mallet Articulated Locomotives, 2-6-8-0", American Engineer and Railroad Journal, Volume 84

No. 10 (October 1910), pp. 108-109.. Works numbers were 34024-34028, 34074-34076 in November 1909; 34104-34105 in December.

Similar to Southern Ls engines (Locobase 293), these M-2s were heavier, and had slightly smaller drivers, smaller "separable" boilers with GN's trademark Belpaire fireboxes, lower superheat ratio, and a different assortment of tubes. Fitted with Emerson feed water heater of 1,777 sq ft (165.09 sq m) in the tubes, which was soon removed. and a. This vessel contained 582 tubes, each measuring 5 ft (1,524 mm) long and 2 1/4" (57 mm) diameter. All of the feed water heater's cross section contained these small tubes except for the center core that contained a 11" (279 mm) flue.

Locobase's specifications show the locomotives after the Emerson superheater was removed.

Another oddity was the use of two different diameters of piston valves. The HP cylinders were supplied by 13" (331 mm) piston valves while 15" (381 mm) piston valve fed the LP cylinders.

They were soon joined by bigger versions of the same design; see Locobase 13537.

Some were simpled; see the M-2 simple entry (Locobase 2800). 22 were converted in 1929-1931 to 69"-drivered 2-8-2s and designated O-7s.


Class M-2 - 2nd batch (Locobase 13536)

Data from GN 1916 Locomotive Diagram supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange and Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 34, pp. 50+. Works numbers were 34824-34833 in June 1910,

Like the first batch described in Locobase 352, this set of GN articulateds were delivered with the trademark Belpaire fireboxes, low superheat ratio, Emerson feed water heater of 1,777 sq ft (165.09 sq m) in the tubes, which was soon removed, and a feedwater heater. One big difference was the addition of more than 100 tubes to the boiler.

Loaded weight on the front three axles was 164,000 lb (74,389 kg) and on the rear four axles, it was 185,000 lb (83,915 kg).

The specifications show the locomotives after the Emerson superheater was removed.

Some were simpled; see the M-2 simple entry (Locobase 2800). 22 were converted in 1929-1931 to 69"-drivered 2-8-2s and designated O-7s.


Class M-2 - simple (Locobase 2800)

Data from GN 1- 1929 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

One of the few classes of locomotives delivered with the odd 2-6-8-0 arrangement. Drury (1993) speculates that it was adopted as a way to get more adhesion. As delivered they were M-1 compound engines (see Locobases 352 and 13536) , but they were simpled in 1926-1928. In keeping with their unusual arrangement, the rebuild gave them front cylinders 22" in diameter, the rear ones 23 1/2", each of which took steam through 13"(330 mm) piston valves. GN calculated the class's tractive effort as 95,500 lb (43,318 kg) based on a 65% cutoff setting on the front set and 85% cutoff on the rear set.

Axle loading on each of the three front axles was 56,000 lb (25,401 kg), which combined for a loaded adhesion weight of 168,000 lb (76,204 kg). The four rear coupled axles each had a 54,000 lb (24,494 kg) axle loading and the set's loaded adhesion weight added up to 216,000 lb (97,976 kg).

See Larry Bohn photograph (http:/www.prostar.com/web/gngoat/gn27013.htm) for an illustration of the rebuild.

Charles R. Wood, in Lines West (New York: Bonanza Books, 1967), commented about these engines (p 66): "Essentially, [they] were slow-speed locomotives and any attempt to push the speed was hard on the engine and track." Watching the side rods carve great swaths of space close to the ground led some enginemen to dub them "grass-cutters." Wood continues: "Rough -riding at any speed above 25 mph [40 kph], they vibrated with a fierce clatter of gangway plates and jingle of cab gauges. As one engineer put it, 'I couldn't even keep my shoelaces tied.'"

Under another photo of the M-2 on p 67, Wood attributes the roughness to large counterweights on the last set of drivers under the cab. And the lack of trailing truck meant that a backing M-2 "...met every rail joint and switch point head on, and changed the angle of direction with a very positive lurch." Yet, Wood concedes, these engines had their place in the GN's scheme of operations:

"[W]ith all their faults, they could move tonnage - not very fast to be sure - but between Butte and Great Falls they would come slogging up the grade under a vast canopy of smoke and cinders while the front bandstand articulated to the curves and the exhaust bounced off the hills and mountainsides."

By the end of the decade, 22 had become O-7 Mikados (Locobase 7448)..

Specifications by Steve Llanso of Sweat House Media
ClassM-2 - 1st batchM-2 - 2nd batchM-2 - simple
Locobase ID352 13,536 2800
RailroadGreat Northern (GN)Great Northern (GN)Great Northern (GN)
CountryUSAUSAUSA
Whyte2-6-8-02-6-8-02-6-8-0
Number in Class352535
Road Numbers1950-19591960-19841950-1984
GaugeStdStdStd
Number Built3525
BuilderBurnham, Williams & CoBaldwinGN
Year190919101926
Valve GearWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)35 / 10.6743.93 / 10.6715 / 4.57
Engine Wheelbase (ft / m)43.93 / 13.3951.58 / 13.3943.92 / 13.39
Ratio of driving wheelbase to overall engine wheebase 0.80 0.85 0.34
Overall Wheelbase (engine & tender) (ft / m)76.21 / 23.2376.21 / 23.2385.42 / 26.04
Axle Loading (Maximum Weight per Axle) (lbs / kg)51,400 / 23,31550,000 / 23,31556,000 / 25,401
Weight on Drivers (lbs / kg)350,000 / 158,758350,000 / 158,758384,000 / 174,180
Engine Weight (lbs / kg)368,700 / 167,240368,700 / 167,240403,000 / 182,798
Tender Loaded Weight (lbs / kg)154,100 / 69,899154,100 / 69,899180,000 / 81,647
Total Engine and Tender Weight (lbs / kg)522,800 / 237,139522,800 / 237,139583,000 / 264,445
Tender Water Capacity (gals / ML)8000 / 30.308000 / 30.3010,000 / 37.88
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)13 / 11.8013 / 11.804500 / 17
Minimum weight of rail (calculated) (lb/yd / kg/m)83 / 41.5083 / 41.5091 / 45.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)55 / 139755 / 139755 / 1397
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80210 / 14.50
High Pressure Cylinders (dia x stroke) (in / mm)23" x 32" / 584x81323" x 32" / 584x81322" x 32" / 559x813
Low Pressure Cylinders (dia x stroke) (in / mm)35" x 32" / 889x81335" x 32" / 889x81323.5" x 32" / 597x813
Tractive Effort (lbs / kg)73,085 / 33150.8473,085 / 33150.84107,620 / 48815.67
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.79 4.79 3.57
Heating Ability
Firebox Area (sq ft / m2)225 / 20.91225 / 20.90258 / 23.97
Grate Area (sq ft / m2)78 / 7.2578 / 7.2578 / 7.25
Evaporative Heating Surface (sq ft / m2)3284 / 305.203750 / 348.385240 / 486.81
Superheating Surface (sq ft / m2)480 / 55.76579 / 53.791490 / 138.42
Combined Heating Surface (sq ft / m2)3764 / 360.964329 / 402.176730 / 625.23
Evaporative Heating Surface/Cylinder Volume213.41243.70372.19
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation15,60015,60016,380
Same as above plus superheater percentage17,62817,62819,984
Same as above but substitute firebox area for grate area50,85050,85066,100
Power L14491518912,734
Power MT198.02228.80511.76

Photos

Reference