Boston & Maine / Concord & Montreal 4-4-2 "Atlantic" Locomotives of 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 Raildata collection.(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 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 Raildata collection.(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.

Specifications by Steve Llanso of Sweat House Media
Class33/JJ-1, J-1a, J-1bJ-1c, d, e, f
Locobase ID5846 2381 16,160
RailroadConcord & Montreal (B&M)Boston & Maine (B&M)Boston & Maine (B&M)
Number in Class14141
Road Numbers33 / 733 / 32003204-32443204-3244
Number Built141
BuilderBurnham, Williams & CoAlcoB&M
Valve GearStephensonStephenson or WalschStephenson or Walsch
Locomotive Length and Weight
Driver Wheelbase (ft) 6.0877
Engine Wheelbase (ft)23.4226.3326.33
Ratio of driving wheelbase to overall engine wheebase 0.26 0.27 0.27
Overall Wheelbase (engine & tender) (ft)54.0853.89
Axle Loading (Maximum Weight per Axle) (lbs)45,40045,400
Weight on Drivers (lbs)74,50090,60092,000
Engine Weight (lbs)128,000178,600181,600
Tender Loaded Weight (lbs)44,50057,500115,000
Total Engine and Tender Weight (lbs)172,500236,100296,600
Tender Water Capacity (gals)400050005000
Tender Fuel Capacity (oil/coal) (gals/tons)71212
Minimum weight of rail (calculated) (lb/yd)627677
Geometry Relating to Tractive Effort
Driver Diameter (in)707979
Boiler Pressure (psi)170200200
High Pressure Cylinders (dia x stroke) (in)19" x 24"19" x 28"19" x 28"
Tractive Effort (lbs)17,88521,75121,751
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.17 4.17 4.23
Heating Ability
Firebox Area (sq ft)145.62176176
Grate Area (sq ft)25.8041.7541.75
Evaporative Heating Surface (sq ft)185128952088
Superheating Surface (sq ft)431
Combined Heating Surface (sq ft)185128952519
Evaporative Heating Surface/Cylinder Volume235.02315.07227.24
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 L1649510,81919,623
Power MT384.40526.53940.46



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