Data from table in June 1907 American Engineer and Railroad Journal and from "'Prairie' Type Locomotive, Northern Pacific Ry," The Locomotive Magazine, Vol XII (15 December 1906), pp. 212-213. See also "Locomotive Boilers with Combustion Chambers", Engineering News, Volume LVI, No 21 (22 November 1906), pp. 531-534; and Northern Pacific Form 7310 Locomotive Cards supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection. Works numbers were 39508-39511 in May 1906, 39512-39527 in June, 40135-40150 in August, 40151-40164 in September, 40878-40888 in November, 40889-40905 in December.
40906-40907 in January 1907, 41924-41933 in February, 41934-41945 in March, 41946-41963 in April, 42235-42260 in May, and 42261-42264 in June.
Procured for light freight service in a wheel arrangement that was a first for the NP. They were among 70 engines procured by the NP that year with combustion chambers. David Van Alstyne, the NP's mechanical superintendent, installed a combustion chamber in T-class engine 2378. He said that the principal reason for doing so was to reduce leakage in tubes (especially in regions of bad water) caused by direct contact with the firebox's fire. Van Alstyne reported that the test had borne out his hopes. The brick arch was in place and the tubes showed little sign of stress or leakage. In his report to the Northwest Railway Club, he added: "What seems to me an especially good feature is ...that it very materially increases the heating surface of the firebox."
Firebox heating surface area included a lone arch tube contributing 9 sq ft (0.83 sq m).
Locobase wonders if it was used to stabilize the arch.
Six were later converted to light Mikados as the W-4s. Ten more were modified as T-1s; see Locobase 918.
Data from NP Locomotive Data Cards in August 2013 by Allen Stanley from his extensive Rail Data Exchange Collection.
Modified from Ts (Locobase 817) in the 1920s. The update was confined to adding a superheater (although the engineer did get a power reverse). The engines retained their 12" (305 mm) piston valves, but cylinder diameter increased by 1/2" (12.7 mm). Firebox heating surface area included 9 sq ft (0.84 sq m) of arch tubes.
Principal Dimensions by Steve Llanso of Middle Run Media | ||
---|---|---|
Class | T | T-1 - superheated |
Locobase ID | 817 | 818 |
Railroad | Northern Pacific (NP) | Northern Pacific (NP) |
Country | USA | USA |
Whyte | 2-6-2 | 2-6-2 |
Number in Class | 150 | 11 |
Road Numbers | 2300-2449 | 2450, 2452, 2454-2457, 2459-2462, 2465 |
Gauge | Std | Std |
Number Built | 150 | |
Builder | Alco-Brooks | NP |
Year | 1906 | 1926 |
Valve Gear | Walschaert | Stephenson |
Locomotive Length and Weight | ||
Driver Wheelbase (ft / m) | 11 / 3.35 | 11 / 3.35 |
Engine Wheelbase (ft / m) | 28.92 / 8.81 | 28.92 / 8.81 |
Ratio of driving wheelbase to overall engine wheelbase | 0.38 | 0.38 |
Overall Wheelbase (engine & tender) (ft / m) | 57.29 / 17.46 | |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | ||
Weight on Drivers (lbs / kg) | 153,500 / 68,946 | 156,000 / 70,760 |
Engine Weight (lbs / kg) | 204,500 / 95,028 | 208,500 / 94,574 |
Tender Loaded Weight (lbs / kg) | 139,500 / 67,359 | 148,500 / 67,359 |
Total Engine and Tender Weight (lbs / kg) | 344,000 / 162,387 | 357,000 / 161,933 |
Tender Water Capacity (gals / ML) | 7000 / 30.30 | 8000 / 30.30 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 12 / 11 | 12 / 11 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 85 / 42.50 | 87 / 43.50 |
Geometry Relating to Tractive Effort | ||
Driver Diameter (in / mm) | 63 / 1600 | 63 / 1600 |
Boiler Pressure (psi / kPa) | 200 / 1380 | 200 / 1380 |
High Pressure Cylinders (dia x stroke) (in / mm) | 21" x 28" / 533x711 | 21.5" x 28" / 546x711 |
Tractive Effort (lbs / kg) | 33,320 / 15113.72 | 34,926 / 15842.19 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.61 | 4.47 |
Heating Ability | ||
Tubes (number - dia) (in / mm) | 306 - 2" / 51 | 173 - 2" / 51 |
Flues (number - dia) (in / mm) | 28 - 5.5" / 140 | |
Flue/Tube length (ft / m) | 13.25 / 4.04 | 13 / 3.96 |
Firebox Area (sq ft / m2) | 235 / 21.84 | 235 / 21.83 |
Grate Area (sq ft / m2) | 43.50 / 4.04 | 43.50 / 4.04 |
Evaporative Heating Surface (sq ft / m2) | 2340 / 217.47 | 1898 / 176.33 |
Superheating Surface (sq ft / m2) | 400 / 37.16 | |
Combined Heating Surface (sq ft / m2) | 2340 / 217.47 | 2298 / 213.49 |
Evaporative Heating Surface/Cylinder Volume | 208.56 | 161.26 |
Computations Relating to Power Output (More Information) | ||
Robert LeMassena's Power Computation | 8700 | 8700 |
Same as above plus superheater percentage | 8700 | 10,179 |
Same as above but substitute firebox area for grate area | 47,000 | 54,990 |
Power L1 | 6579 | 11,906 |
Power MT | 283.47 | 504.77 |