In 1928, another five 4-8-2s were delivered. This time, they came from the Baldwin Locomotive Works and were designated as Class M-2 and assigned road numbers 905 through 909. These locomotives were very similar to the Class M-1s except for an increase in total weight. Later, the boiler pressure of these last five oil burners was raised to 225 psi, which increased the tractive effort to 57,300 pounds.
There are no surviving T&P "Mountains".
|Class||Road Numbers||Year Built||Builder|
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.
The first five Mountains procured for passenger service by the T & P came from Schenectady in 1926 (See Locobase 229). The current entry describes the later five that arrived three years later. Like the M-1s, the M-2s had fireboxes whose heating surface area included 119 sq ft (11.05 sq m) in the combustion chamber and two Nicholson Thermic Syphons adding 70 sq ft (6.5 sq m).
The Walschaert valve gear operated 14" (356 mm) piston valves with 8" (203 mm) travel. Also like the M-1s, the M-2 boiler was fitted with the Coffin feedwater heater. The differences between the two classes were admittedly small: a slight increase in grate area and, consequently, in firebox heating surface and a more substantial reduction in superheater area.
Al1 ten 4-8-2s handled the long-haul passenger trains such as the Sunshine Special, the Texan, and the Southerner. The T & P was an early adopter of an all-diesel motive-power roster and the last steam run of any sort came in 1951.
|Specifications by Steve Llanso|
|Railroad||Texas & Pacific (T & P)||Texas & Pacific (T & P)|
|Locomotive Length and Weight|
|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 lbs||61500 lbs|
|Weight on Drivers||245500 lbs||245600 lbs|
|Engine Weight||360500 lbs||361400 lbs|
|Tender Light Weight||280100 lbs||291666 lbs|
|Total Engine and Tender Weight||640600 lbs||653066 lbs|
|Tender Water Capacity||14000 gals||14000 gals|
|Tender Fuel Capacity (oil/coal)||6000 gals||6000 gals|
|Minimum weight of rail (calculated) on which locomotive could run||102 lb/yard||102 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||210 psi||225 psi|
|Cylinders (dia x stroke)||27" x 30"||27" x 30"|
|Tractive Effort||53477 lbs||57296 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.59||4.29|
|Firebox Area||404 sq. ft||409 sq. ft|
|Grate Area||80.30 sq. ft||81.12 sq. ft|
|Evaporative Heating Surface||3768 sq. ft||3774 sq. ft|
|Superheating Surface||1110 sq. ft||1032 sq. ft|
|Combined Heating Surface||4878 sq. ft||4806 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||189.53||189.84|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||16863||18252|
|Same as above plus superheater percentage||20741||22085|
|Same as above but substitute firebox area for grate area||104353||111350|