Lehigh Valley 4-8-4 "Northern" Locomotives in the USA

The Lehigh Valley Railroad took delivery of two 4-8-4s in 1931. Road number 5100 was built by the Baldwin Locomotive Works and was designated Class T-1a. It had 70" drivers, 27 x 30 cylinders, a boiler pressure of 250 psi, a tractive effort of 66,400 lbs and weighed 413,170 pounds. Road number 5200 came from the American Locomotive Company and was designated Class T-2a. It had 70" drivers, 26 x 32 cylinders, a boiler pressure of 255 psi, a tractive effort of 66,700 lbs and weighed 424,000 pounds. These two locomotives were delivered for trials, with 10 more of the Class T-1a 4-8-4s delivered from Baldwin in 1932, and 10 more of the Class T-2a 4-8-4s delivered from ALCO, also in 1932.

The Lehigh Valley gave its 4-8-4 type locomotives a local name, rather than the "Northern" designation. The name "Wyoming" was selected. The Wyoming Valley is a historic section of the Susquehanna Valley that is served by the railroad.

In 1934, five heavier 4-8-4s were delivered by Baldwin as dual purpose locomotives. They were designated Class T-3 and assigned road numbers 5125 through 5129. They had 77" drivers, 27 x 30 cylinders, a boiler pressure of 275 lbs, a tractive effort of 66,500 lbs and weighed 441,400 pounds.

During World War II, the Lehigh Valley needed additional motive power but because of wartime restrictions, it could not build newly designed locomotives. Therefore, 10 duplicates of the Class T-2a Wyomings were ordered from ALCO and delivered in 1943. They were very similar to the older Class T-2a locomotives except they were 17,000 lbs heavier.

There are no surviving LV "Wyomings".


ClassRoad NumbersBuilderYear Built
T-1a5100 - 5110BLW1931, 32
T-2a5200 - 5210ALCO1931, 32
T-2b5211 - 5220ALCO1943
T-35125 - 5129BLW1934, 35

Class Details by Steve Llanso of Sweat House Media

Class T-1 (Locobase 263)

Data from LV 3-1934 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 82, pp. 87+. (Thanks to Chris Hohl for 10 April 2015 spotting and reporting the differences between the 5100 and the other ten locomotives and correcting the booster's tractive effort.) Works numbers were 61615 in March 1931, 61672-61674 in April 1932, and 61675-61681 in May.

Known as "Wyomings" in Lehigh Valley service and intended for heavy fast trains over maximum grades of 1 1/2%. When fitted, an unusually powerful side rod tender booster added 18,360 lb (8,328 kg or 81.67 kN) to the starting tractive effort.

Chris Hohl noted some differences between the 1931 loner and the ten engines supplied a year later: "5100 had Walschaert valve gear, and an Elesco K-50 feed water heater at the top/crown of smokebox ... her tender weighed 363,000 lbs. Her tender capacities were 28 tons [25.45 metric tons] & 18,000 gallons [68,130 litres]." The Baldwin specs estimated a total engine weight for the 5100 of 425,000 lb (192,777 kg), but the LV diagrams report 408,000 lb (185,066 kg).

Production T-1s used a Worthington feed water heater and actuated the 12" (305 mm) piston valves with Baker gear. In all, the firebox's heating surface area included 143 sq ft (13.3 sq m) in Nicholson thermic syphons, three in the firebox and one in the combustion chamber. An additional 92 sq ft (8.5 sq m) came from the shell of the chamber. A Standard BK stoker fed the coal. The front truck (bogie) axles turned in Timken roller bearings; it weighed 5,070 lb (2,300 kg) more than the one under the 5100.

The Lehigh Valley laid out the schedule it expected this engine to keep from Frontier (near Niagara Falls, NY) to Tidewater (Jersey City, NJ) while hauling 3,000 short tons:

Suspension Bridge to Manchester 3 hours 30 minutes

Buffalo to Manchester 3 hours 0 minutes

Manchester to Sayre (Pa) 3 hours 0 minutes

Sayre to Coxton 2 hours 15 minutes

Coxton to Mahoning (Pa) 3 hours 0 minutes

Mahoning to Jersey City (NJ) 4 hours 0 minutes

Class T-2, T-2a (Locobase 16286)

Data from LV 3-1934 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Many thanks to Chris Hohl for his 20 May 2017 email and builder's card that supplied the data for the prototype, which also corrected the road-number range for this first class.) Works numbers were 68546 in March 1931, 68610-68611 in April 1932, 68612-68619 in May.

These 11 locomotives consisted of the Schenectady prototype and the 1932 batch of Wyomings. 5100 appeared at the same time as Baldwin's T-1 and had roughly the same characteristics. Intriguing differences included a different path to very similar amount of cylinder volume. Alco's cylinders measured an inch less in diameter, but allowed two more inches of stroke.

Like the Baldwin T-1 prototype shown in Locobase 263, this Schenectady rival used an Elesco feed water heater and carried the characteristic cylinder over 5200's headlight. The 5200's combustion chamber was 6" (152 mm) longer than that of the T-1 (prototype and production) and the engine wheelbase was 8" (203 mm) longer. Firebox heating surface included 131 sq ft (12.7 sq m) of arch tubes in the firebox and Nicholson thermic syphons in the firebox and combustion chamber. The class used one of the most powerful trailing-truck boosters ever fitted to a locomotive--one adding 18,360 lb (8,328 kg) to the starting tractive effort.

Eleven years later, Alco delivered ten T-2b with very few differences; see Locobase 265.

Class T-2b (Locobase 265)

Data from 1947 Locomotive Cyclopedia and from LV 3 -1934 Locomotive Diagrams, the latter supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for a 20 May 2017 email containing a question about the tender booster.) Works numbers were 68610-68611 in April 1932, 68612-68619 in May (T-2) and 70839-70848 in October 1943.

The first eleven Alco Wyomings were built for the Lehigh Valley in 1931 and 1932; their description appears in Locobase 16286.

T-2bs came a decade later and repeated the design with some detail differences. One of these was a reduction in the number of small tubes. At the same time, superheater area decreased by 148 sq ft (13.75 sq m) and the firebox heating surface included 131 sq ft (12.7 sq m) of arch tubes in the firebox and Nicholson thermic syphons in the firebox and combustion chamber. Trailing truck booster tractive effort shrank from 18,360 lb (8,328 kg or 81.67 kN) to 12,300 lb (5,579 kg or .54.71 kN). Spoked drivers were replaced by Boxpoks on all four driving axles.

Most of the changes probably reflected limited availabilities of materials and components, which meant using heavier steel and reducing demands on already stretched maintenance staff.

Class T-3 (Locobase 264)

Data from LV 3-1934 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for his 15 January 2019 noting the last two engines' differences in weights and journal bearings.) Works numbers ran 61808-61810 in December 1934 and 61811-61812 in January 1935.

Obviously based on Baldwin's T-1s of 1931-1932, this quintet had taller drivers, boiler pressed to a higher PSI, and a larger grate. Firebox had thermic syphons and the boiler had a Worthington feed water heater. Chris Hohl noted that the last two--5128-5129--in the class were delivered with Timken roller bearings on all axles; the earlier three used Timkens only in the leading truck axles. 5128-5219 were also credited with 2,200 lb (998 kg) less weight on the drivers (all four axles carried less weight), possibly as a result of the new bearing system. At the same time, all four axles in the two trucks carried more than four tons (8,540 lb/3,874 kg) more weight.

Drury (1993) says that these Wyomings weren't passenger engines, but "occasionally pulled milk trains, where their high drivers were useful -- a slow milk train can quickly become a yogurt train." They would also head up the famous Black Diamond express train.

Principal Dimensions by Steve Llanso of Sweat House Media
ClassT-1T-2, T-2aT-2bT-3
Locobase ID263 16286 265 264
RailroadLehigh Valley (LV)Lehigh Valley (LV)Lehigh Valley (LV)Lehigh Valley (LV)
Number in Class1111205
Road Numbers5100-51105200-52105201-52205125-5129
Number Built1111205
Valve GearBakerBakerBakerBaker
Locomotive Length and Weight
Driver Wheelbase (ft / m)19.25 / 5.8719.25 / 5.8719.25 / 5.8720 / 6.10
Engine Wheelbase (ft / m)44.92 / 13.6945.58 / 13.8945.58 / 13.8945.92 / 14
Ratio of driving wheelbase to overall engine wheebase 0.43 0.42 0.42 0.44
Overall Wheelbase (engine & tender) (ft / m)94.87 / 28.9295.46 / 29.1095 / 28.9695.17 / 29.01
Axle Loading (Maximum Weight per Axle) (lbs / kg)67,500 / 30,61868,300 / 30,980
Weight on Drivers (lbs / kg)270,000 / 122,470268,000 / 121,563374,500 / 169,871272,200 / 123,468
Engine Weight (lbs / kg)413,170 / 187,411422,000 / 191,416451,000 / 204,570435,000 / 197,313
Tender Loaded Weight (lbs / kg)398,300 / 180,666358,800 / 162,749389,100 / 176,493389,000 / 176,448
Total Engine and Tender Weight (lbs / kg)811,470 / 368,077780,800 / 354,165840,100 / 381,063824,000 / 373,761
Tender Water Capacity (gals / ML)20,000 / 75.7618,000 / 68.1820,000 / 75.7620,000 / 75.76
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)30 / 27.3028 / 25.5030 / 27.3030 / 27.30
Minimum weight of rail (calculated) (lb/yd / kg/m)113 / 56.50112 / 56156 / 78113 / 56.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)70 / 177870 / 177870 / 177877 / 1956
Boiler Pressure (psi / kPa)250 / 17.20255 / 17.60255 / 17.60275 / 19
High Pressure Cylinders (dia x stroke) (in / mm)27" x 30" / 686x76226" x 32" / 660x81326" x 32" / 660x81327" x 30" / 686x762
Tractive Effort (lbs / kg)66,391 / 30114.4966,982 / 30382.5666,982 / 30382.5666,391 / 30114.49
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.07 4.00 5.59 4.10
Heating Ability
Firebox Area (sq ft / m2)490 / 45.52508 / 47.19494 / 45.89507 / 47.10
Grate Area (sq ft / m2)88.30 / 8.2088.30 / 8.2088.30 / 8.2096.50 / 8.97
Evaporative Heating Surface (sq ft / m2)5422 / 503.725441 / 505.485376 / 499.445439 / 505.30
Superheating Surface (sq ft / m2)2256 / 209.592243 / 208.382095 / 194.632056 / 191.01
Combined Heating Surface (sq ft / m2)7678 / 713.317684 / 713.867471 / 694.077495 / 696.31
Evaporative Heating Surface/Cylinder Volume272.73276.70273.39273.59
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation22,07522,51722,51726,538
Same as above plus superheater percentage28,47729,04628,82133,703
Same as above but substitute firebox area for grate area158,025167,107161,242177,070
Power L141,33742,61640,39647,004
Power MT1350.111402.27951.221522.79

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