The first batch of twenty locomotives, designated Class T-1a, arrived in 1928 and had 63" diameter drivers, 27.5" x 30" cylinders, a boiler pressure of 240 psi, they exerted 66,500 pounds of tractive effort and each weighed 390,200 pounds. The last five, designated Class T-1b, were delivered in 1929 and were similar except they had a tractive effort of 68,990 pounds and a weight of 403,000 pounds.
From the beginning, the B&M had problems with their Lima built "Berkshires". The problem was with the trailing four-wheel truck. Because of the large firebox and large ash pan the locomotive had to have an articulated frame. The back end of the firebox had to rest on a moving base and it was subject to buffeting and twisting, resulting in chronic leakage at the mud ring, side sheet stay bolts and the throat sheet, as it tried to wiggle from side to side to follow the motion of the trucks. Also, this arrangement would sometimes cause the rear wheels to derail while backing up.
During the closing months of World War II, the western railroads were in dire need of motive power to handle the shift in material and personnel from the European front to the war in the Pacific. The Boston & Maine was never really satisfied with its Lima built "Berkshires" and jumped at the chance to help the war effort and to unload its "lemons". The B&M sold ten "Berkshires" to the Southern Pacific and seven to the Santa Fe.
There are no surviving B&M 2-8-4 "Berkshire" type locomotives.
Class | Qty. | Road Numbers | Year Built | Builder | Notes |
---|---|---|---|---|---|
T-1a | 20 | 4000-4019 | 1928 | Lima | 1 |
T-1b | 5 | 4020-4024 | 1929 | Lima | 2 |
Data from 1927 and 1947 Boston & Maine Description of Locomotives books supplied in May 2005 and ATSF 1953 Locomotive Diagrams Steam Assorted supplied in 2016 by Allen Stanley from his extensive Rail Data Exchange collection. See also George H Drury, Guide to North American Steam Locomotives-Revised edition (Waukesha, WI: 1993, rev ed 2015), p. 85 (Thanks to Chris Hohl for questions about the valve gear and tenders that led to a note about the T-1a and an additional note about the T-1b's tender as well as for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error . Hohl's 27 April 2020 email supplied information and a spreadsheet providing details on the 4197 .)
Boiler had Coffin feedwater heater wrapped as a collar around the smokebox, valve motion had limited cutoff. Firebox heating surface included 22 sq ft (2.05 sq m) of arch tubes and 99 sq ft (9.2 sq m) of thermic syphons. 14" (356 mm) piston valves supplied steam to the cylinders. T-1as (works numbers 7277-7296 in May 1928, road numbers 4000-4019) were delivered with Baker valve gear, but all had the Walschaert gear by 1947.
T-1b (works numbers 7374-7378 in August 1929, engine numbers 4020-4024) engine weight was 403,000 lb (182,798 kg). Indeed, by 1947, engine weight had climbed to 406,900 lb (184,567 kg) for the whole class. Boston and Albany A1 (Locobase 46) and Illinois Central #7000 (Locobase 48) very similar.
The T-1b's tenders were much bigger. They weighed 139,000 lb (63,049 kg) empty and 330,600 lb (149,958 kg) when carrying 17,500 US gallons (66,238 litres) and 26 tons (23.6 metric tons) of coal.
Drury (1993) comments that the design of the trailing truck, which encouraged derailments and the lack of adhesion on the drivers, which made them slippery, contributed to the railroad's disenchantment with the class. He also noted that the rear of the firebox was supported by the trailing truck, and "as the truck swiveled, twisting forces were placed on the firebox, which wasn't designed for such stress."
Seven of these were sold to the Santa Fe in July and August 1945 as that railroad's 4193 class. Some sources say the class was converted to oil-burning but the Santa Fe diagrams available to Locobase show all seven as coal burners. Hohl's spreadsheet showed they now had much larger tenders carrying 23 tons (20.9 metric tons) of coal and 17,500 US gallons (66,238 litres) of water. Fully loaded, the tenders weighed 328,600 lb (149,051 kg). Six retained their Coffin feed water heaters, two (4197 and 4199) received Walschaert gear and Elesco feed water heaters,, but all but one were generally left alone.
The Santa Fe rebuilt the 4197 at the Topeka Shops with Walschaert gear, an Elesco feed water heater, boiler pressed to 270 psi (18.62 bar), smaller 27" (686 mm) diameter and longer 32" (813 mm) stroke cast steel cylinders, multiple-bearing crosshead. The new combination of boiler pressure and cylinder volume raised tractive effort to a calculated 84,980 lb (378.01 kN). The Santa Fe, however, rated the engine at 70,100 lb (31,797 kg or 311.89 kN) tractive effort, which suggests a much lower operating pressure of about 225 psi (15.52 psi) for all seven engines. Chris Hohl's review of several Santa Fe diagrams determined that the Santa Fe "generally used a constant ranging from 70%-75%" as part of its tractive effort calculation, which would have resulted in the lower tractive effort.
The unconverted engines lasted only a short time on the Santa Fe and were sent to the ferro-knacker in October and November 1949. The 4197's rebuild gave her more life; she was scrapped with the other 2-8-4s in 1954.
Principal Dimensions by Steve Llanso of Middle Run Media | |
---|---|
Class | T-1a/T-1b |
Locobase ID | 47 |
Railroad | Boston & Maine (B&M) |
Country | USA |
Whyte | 2-8-4 |
Number in Class | 25 |
Road Numbers | 4000-4024 |
Gauge | Std |
Number Built | 25 |
Builder | Lima |
Year | 1928 |
Valve Gear | Baker |
Locomotive Length and Weight | |
Driver Wheelbase (ft / m) | 16.50 / 5.03 |
Engine Wheelbase (ft / m) | 41.70 / 12.71 |
Ratio of driving wheelbase to overall engine wheelbase | 0.40 |
Overall Wheelbase (engine & tender) (ft / m) | 80.30 / 24.48 |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | 65,900 / 29,892 |
Weight on Drivers (lbs / kg) | 261,800 / 118,751 |
Engine Weight (lbs / kg) | 406,900 / 184,567 |
Tender Loaded Weight (lbs / kg) | 216,400 / 98,158 |
Total Engine and Tender Weight (lbs / kg) | 623,300 / 282,725 |
Tender Water Capacity (gals / ML) | 12,000 / 45.45 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 18 / 16 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 109 / 54.50 |
Geometry Relating to Tractive Effort | |
Driver Diameter (in / mm) | 63 / 1600 |
Boiler Pressure (psi / kPa) | 210 / 1650 |
High Pressure Cylinders (dia x stroke) (in / mm) | 28" x 30" / 711x762 |
Tractive Effort (lbs / kg) | 66,640 / 30227.43 |
Booster (lbs) | 12,000 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.93 |
Heating Ability | |
Tubes (number - dia) (in / mm) | 86 - 2.25" / 57 |
Flues (number - dia) (in / mm) | 204 - 3.5" / 89 |
Flue/Tube length (ft / m) | 20 / 6.10 |
Firebox Area (sq ft / m2) | 405 / 37.63 |
Grate Area (sq ft / m2) | 100 / 9.29 |
Evaporative Heating Surface (sq ft / m2) | 5131 / 476.86 |
Superheating Surface (sq ft / m2) | 2135 / 198.42 |
Combined Heating Surface (sq ft / m2) | 7266 / 675.28 |
Evaporative Heating Surface/Cylinder Volume | 239.99 |
Computations Relating to Power Output (More Information) | |
Robert LeMassena's Power Computation | 21,000 |
Same as above plus superheater percentage | 27,090 |
Same as above but substitute firebox area for grate area | 109,715 |
Power L1 | 27,197 |
Power MT | 916.10 |