Texas & Pacific 4-8-2 "Mountain" Type Locomotives

Class M-1 (Locobase 229)

5 built in 1926 by Alco and described in Railway Age Gazette. Data from T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Firebox had combustion chamber and two Nicholson Thermic Syphons of 70 sq ft total heating surface, boiler fitted with Elesco feedwater heater. The Baldwin engines of 1928 had some slight differences; see Locobase 8511.

Al1 ten 4-8-2s handled the long-haul passenger trains such as the Sunshine Special, the Texan, and the Southerner.

Class M-2 (Locobase 8511)

Data from T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

The first 5 Mountains procured for passenger service by the T & P came from Schenectady in 1926 (See Locobase 229). The current entry describes the later 5 that arrived 3 years later. Al1 ten 4-8-2s handled the long-haul passenger trains such as the Sunshine Special, the Texan, and the Southerner.

Like the M-1s, the M-2s had boilers with combustion chamber and fireboxes equipped with two Nicholson Thermic Syphons of 70 sq ft total heating surface. Also like the M-1s, the M-2 boiler was fitted with Elesco feedwater heater. The differences were admittedly small: a slight increase in grate area and, consequently, in firebox heating surface and a more substantial reduction in superheater area.

Specifications
ClassM-1M-2
Locobase ID2298511
RailroadTexas & Pacific (T & P)Texas & Pacific (T & P)
Whyte4-8-24-8-2
Road Numbers900-904905-909
GaugeStdStd
BuilderAlco-SchenectadyBaldwin
Year19261928
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase20'20'
Engine Wheelbase43.25'43.25'
Ratio of driving wheelbase to overall engine wheebase 0.46 0.46
Overall Wheelbase (engine & tender)84'84'
Axle Loading (Maximum Weight per Axle)61400 lbs61500 lbs
Weight on Drivers245500 lbs245600 lbs
Engine Weight360500 lbs361400 lbs
Tender Light Weight280100 lbs291666 lbs
Total Engine and Tender Weight640600 lbs653066 lbs
Tender Water Capacity14000 gals14000 gals
Tender Fuel Capacity (oil/coal)6000 gals6000 gals
Minimum weight per yard of rail on which locomotive could run102.29 lb rail102.33 lb rail
Geometry Relating to Tractive Effort
Driver Diameter73"73"
Boiler Pressure210 psi225 psi
Cylinders (dia x stroke)27" x 30"27" x 30"
Tractive Effort53477 lbs57296 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.59 4.29
Heating Ability
Firebox Area404 sq. ft409 sq. ft
Grate Area80.30 sq. ft81.12 sq. ft
Evaporative Heating Surface37683774
Superheating Surface11101032
Combined Heating Surface48784806
Evaporative Heating Surface/Cylinder Volume189.53189.84
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1686318252
Same as above plus superheater percentage20700.2122171.28
Same as above but substitute firebox area for grate area104145.54111785.67
Power L120277.6620802.11
Power MT728.38746.92

Credits

Introduction and specifications provided by Steve Llanso of Sweat House Media.