Boston & Maine / Concord & Montreal 4-4-2 "Atlantic" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class 33/J (Locobase 5846)

Data from "Passenger Locomotive for the Concord & Montreal Railroad," American Engineer & Railroad Journal (June 1895), p. 270. See also DeGolyer, Volume 19, p. 219. Works number was 14287 in April 1895.

Within a couple of months of each other, the AERJ described engines supplied to the Concord & Montreal. This is the Atlantic that the AERJ notes offers all the qualities of the design -- firebox behind the drivers, a guiding truck -- except for high drivers.

This engine was absorbed by the Boston & Maine as its lone Class J. In Harry A Frye, Minuteman steam: Boston & Maine steam locomotives, 1911-1958 (Littleton, MA : Boston and Maine Railroad Historical Society, 1982), Harry Frye said the B&M call these Atlantics "Trailers", for the trailing truck. It was scrapped in October 1927.


Class J-1, J-1a, J-1b (Locobase 2381)

Data from Boston & Maine 1947 diagrams and 1919 Locomotive Classification, supplied by Allen Stanley in May 2005 from his extensive Rail Data Exchange.(Many thanks to Chris Hohl for his 21 November 2015 email and spreadsheet detailing the specs for all of the B&M Atlantic variants.) Schenectady works numbers were 25076-25081 in May 1902 and 42845-42854 in May 1907. Manchester added 25 more: 45137-45145 in 1908, 45146-45161 in January-April 1909.

Class J-1 3204-3209 arrived in 1902, 3210-3219 -- J-1a -- arrived in 1907, and 3220-3239 -- J-1b -- were delivered in 1908-1909.

All had 11" (279 mm) piston valves and 23 sq ft (2.14 sq m) of arch tubes, which contributed to the firebox heating surface area. Weight on drivers and overall engine weight increased with each batch.

Subclass Builder Year 1911 Road # Adhesion weight Engine weight.

J-1 Schenectady 1902 3204-3209 81,000 lb 159,600

J-1a Schenectady 1907 3210-3219 88,200 lb 170,000

J-1b Manchester 1908-1909 3220-3244 90,000 lb 175,000

The 25 Manchester engines were delivered with Walschaert outside constant-lead radial valve gear.

Three--3240, 3242, 3244--were assigned to the Sullivan County Railroad and numbered 9, 11, and 10, respectively. Three more--3231, 3241, 3243--to the Vermont Valley and numbered 21, 29, and 30. 3242-3243 were placed back on the B&M roster in 1911. The other four engines regained their B&M numbers in 1926..

Thirty-one were superheated in the 1920s; see Locobase 16160.


Class J-1c, d, e, f (Locobase 16160)

Data from B&M 6 - 1939 Locomotive Diagrams and B&M 1 - 1927 Locomotive Classification supplied by Allen Stanley in August 2013 from his extensive Rail Data Exchange.(Many thanks to Chris Hohl for his 21 November 2015 email and spreadsheet detailing the specs for all of the B&M Atlantic variants; The work alerted Locobase to the lack of a record on the superheater conversion, which prompted this entry. Other questions raised in a 2 February 2016 email also prompted clarifications.)

Alco's Schenectady and Manchester work supplied 41Atlantics to the B&M in 1902-1909; see Locobase 2381. The B&M superheated most of its locomotives and most of the J-1 class was modified. By 1927, 25 of the 41 from all four subclasses of J-1s had been superheated. 32505 and 3209 from the 1902 Schenectady batch had been redesignated J-1f and J-1c, respectively. Four of the 1907 J-1a--3214, 3216, 3218-3219--were now J-1d.

Of the Manchester class, 3221-3230, 3232, 3234-3244 were converted to J-1e by 1928.

The resulting superheat ratio was adequate, but not ambitious and the overhaul added less than a ton to the engine weight. Stephenson link locomotives (the 15 Schenectadies) kept that valve gear and the 25 Manchesters retained the Walschaert gear. All kept their 11" (279 mm) piston valves and 23 sq ft (2.14 sq m) of arch tubes. Most of the superheated engines received new fireboxes as well.

By 1939, all of the earlier locomotives had been retired and the number of J-1es had been reduced to 20.

Principal Dimensions by Steve Llanso of Middle Run Media
Class33/JJ-1, J-1a, J-1bJ-1c, d, e, f
Locobase ID5846 2381 16160
RailroadConcord & Montreal (B&M)Boston & Maine (B&M)Boston & Maine (B&M)
CountryUSAUSAUSA
Whyte4-4-24-4-24-4-2
Number in Class14141
Road Numbers33 / 733 / 32003204-32443204-3244
GaugeStdStdStd
Number Built141
BuilderBurnham, Williams & CoAlco - multiple worksB&M
Year189519021920
Valve GearStephensonStephenson or WalschStephenson or Walsch
Locomotive Length and Weight
Driver Wheelbase (ft / m) 6.08 / 1.857 / 2.137 / 2.13
Engine Wheelbase (ft / m)23.42 / 7.1426.33 / 8.0326.33 / 8.03
Ratio of driving wheelbase to overall engine wheelbase 0.26 0.27 0.27
Overall Wheelbase (engine & tender) (ft / m)54.08 / 16.4853.89 / 16.43
Axle Loading (Maximum Weight per Axle) (lbs / kg)45,400 / 20,59345,400 / 20,593
Weight on Drivers (lbs / kg)74,500 / 33,79390,600 / 41,09692,000 / 41,731
Engine Weight (lbs / kg)128,000 / 58,060178,600 / 81,012181,600 / 82,372
Tender Loaded Weight (lbs / kg)44,500 / 20,18557,500 / 26,082115,000 / 52,163
Total Engine and Tender Weight (lbs / kg)172,500 / 78,245236,100 / 107,094296,600 / 134,535
Tender Water Capacity (gals / ML)4000 / 15.155000 / 18.945000 / 18.94
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)7 / 612 / 1112 / 11
Minimum weight of rail (calculated) (lb/yd / kg/m)62 / 3176 / 3877 / 38.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)70 / 177879 / 200779 / 2007
Boiler Pressure (psi / kPa)170 / 1170200 / 1380200 / 1380
High Pressure Cylinders (dia x stroke) (in / mm)19" x 24" / 483x61019" x 28" / 483x71119" x 28" / 483x711
Tractive Effort (lbs / kg)17,885 / 8112.5121,751 / 9866.1021,751 / 9866.10
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.17 4.17 4.23
Heating Ability
Tubes (number - dia) (in / mm)234 - 2" / 51326 - 2" / 51165 - 2" / 51
Flues (number - dia) (in / mm)24 - 5.375" / 137
Flue/Tube length (ft / m)14 / 4.2716 / 4.8816 / 4.88
Firebox Area (sq ft / m2)145.62 / 13.53176 / 16.17176 / 16.35
Grate Area (sq ft / m2)25.80 / 2.4041.75 / 3.8841.75 / 3.88
Evaporative Heating Surface (sq ft / m2)1851 / 172.032895 / 269.052088 / 193.98
Superheating Surface (sq ft / m2)431 / 40.04
Combined Heating Surface (sq ft / m2)1851 / 172.032895 / 269.052519 / 234.02
Evaporative Heating Surface/Cylinder Volume234.90315.02227.20
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation438683508350
Same as above plus superheater percentage438683509770
Same as above but substitute firebox area for grate area24,75535,20041,184
Power L1649110,81719,620
Power MT384.17526.43940.32

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