Each of the B&M "Mountains" carried a name in addition to its road number. These names were selected from contest entries and were assigned as noted below.
Thirteen of these locomotives (road numbers 4100 through 4112) were sold to the B&O in 1947 and the remaining five were retired in 1955 and 1956 and were scrapped shortly after.
There were four R-1 classes comprising eighteen engines -- all were named in contests. All had integral cast-steel beds, 14" (356 mm) piston valves. R-1a used spoked wheels on all driving axles and had the safety valve stand located just ahead of the cab. R-1b had Baldwin discs on the main driven axle, and R-1ds had Baldwin discs on all driving axles. Safety valves were relocated in the last three subclasses to a mid-boiler position between the small steam dome and large sand dome
These first thirteen were delivered with Coffin size C-85 feedwater heaters. The R-1ds used Worthington 5-SAs.
The first three subclasses trailed twelve-wheel tenders on two three-axle trucks, each wheel of 36" (914 mm) diameter; tender wheelbase came to 36 ft 1 in (11 m). They carried 20,000 US gallons (75,700 litres) of water and 21 tons of coal when delivered. They weighed about 369,000 lb (167,376 kg) loaded. Later, they used larger tenders, still rolling on two six-wheel trucks, that held a bit more water and 2 1/2 tons more coal. These are shown in the Locobase specs above.
R-1d tenders had fourteen larger (42") wheels that were carried in three two-axle trucks and a single trailing truck, an arrangement that reduced the tender's wheelbase to 32 ft 8 in (9.96 m) . Fuel capacity stayed at 21 tons, but water capacity increased to 23,000 gallons (87,055 litres). Tender weight increased to 399,600 lb (181,256 kg).
R-1a (1935) works numbers 61822-61826. Loaded weight was 416,100 lb.
4101 Hannah Dustin
4103 Oliver Wendell Holmes
4104 Bee & Emma
R-1b (1937) works numbers 62033-62037. Loaded weight was 416,100 lb.
4105 Powwow River
4106 Little John
4108 Lily Pons
4109 Bumble Bee
R-1c (1939) works numbers 62318-62319, 6232. Loaded weight 414,960 lb.
4110 Calvin Coolidge
R-1d (1941) works numbers 62536-62540; weighed 415,200 lb.
4113 Black Arrow
4115 Casey Jones
4116 American Progress
4100-4112 were sold to the B&O in 1947as T-4 class 5650-5612 as the B&M dieselized. The last 5 remained in B & M service until 1955-1956.
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Railroad||Boston & Maine (B&M)|
|Number in Class||18|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||19.25 / 5.87|
|Engine Wheelbase (ft / m)||44.17 / 13.46|
|Ratio of driving wheelbase to overall engine wheebase||0.44|
|Overall Wheelbase (engine & tender) (ft / m)||92.67 / 28.25|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||68,900 / 31,253|
|Weight on Drivers (lbs / kg)||269,400 / 122,198|
|Engine Weight (lbs / kg)||416,100 / 188,740|
|Tender Loaded Weight (lbs / kg)||372,700 / 169,054|
|Total Engine and Tender Weight (lbs / kg)||788,800 / 357,794|
|Tender Water Capacity (gals / ML)||20,200 / 76.52|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||22.50 / 20.50|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||112 / 56|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||73 / 1854|
|Boiler Pressure (psi / kPa)||240 / 16.50|
|High Pressure Cylinders (dia x stroke) (in / mm)||28" x 31" / 711x787|
|Tractive Effort (lbs / kg)||67,918 / 30807.12|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||3.97|
|Firebox Area (sq ft / m2)||475 / 44.13|
|Grate Area (sq ft / m2)||79 / 7.34|
|Evaporative Heating Surface (sq ft / m2)||4511 / 419.08|
|Superheating Surface (sq ft / m2)||1924 / 178.74|
|Combined Heating Surface (sq ft / m2)||6435 / 597.82|
|Evaporative Heating Surface/Cylinder Volume||204.18|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||18,960|
|Same as above plus superheater percentage||24,648|
|Same as above but substitute firebox area for grate area||148,200|