Ann Arbor 4-4-2 "Atlantic" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class I-1/E-6 (Locobase 16570)

Data fromAA-M&LS 1 - 1928 locomotive diagram book dated supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for his 1 December 2021 commenting on differences between the 204 and the earlier locomotives. Locobase concluded that the 204 deserved its own entry.) Works numbers were 43298-43301 in July 1907 and 46202 in June 1909.

Locobase 7339 shows four relatively small Atlantics procured relatively late in that wheel arrangement's short period of ascendancy as a passenger engine. Apparently satisfied with the design, the AA purchased another two years, paying $14,000.

Retaining the essentials of boiler, grate, and fireboz heating surface areas (including 20 sq ft (1.86 sq m) of arch tubes in the firebox), Alco and the AA focused on the running gear. In place of the slide valves, the new engine sported piston valves with a travel of 6" (152 mm). Inside Stephenson link motion was replaced by outside radial valve gear. (Although these substitutions heralded a superheater update, the 204 never had one installed. o see what a superheated version of this design might have looked like, go to Locobase 16386, which describes the very similar 1920 pair of Atlantics delivered to short line Pittsburg & Shawmut in western Pennsylvania.)

Other changes iincluded a longer tender (with the same fuel and water capacities as the earlier one) and slightly shorter smokebox.

When the Ann Arbor joined the Wabash in 1925, that railroad redesignated the I-1 as E-6 and gave it road number 1614. Even in February 1950, the class still averaged 279 miles per day per engine, considerably more than any other class. The 1614 closed the books on these Atlantics when it was scrapped in March 1951.


Class I/E-5 (Locobase 7339)

Data fromAA-M&LS 1 - 1928 locomotive diagram book dated supplied in May 2005 by Allen Stanley from his extensive Rail Data (Thanks to Chris Hohl for his 1 December 2021 commenting on differences between the 204 and the earlier locomotives. Locobase concluded that the 204 deserved its own entry.) Works numbers were 43298-43301 in July 1907..

These were relatively small Atlantics procured relatively late in that wheel arrangement's short period of ascendancy as a passenger engine. The driver diameter implies local passenger rather than express. The first four were bought in July 1907 and delivered four months later for a total cost of $54,794.46.

The diagram notes that 200-201 had the number of tubes and consequently the total heating surface as shown. 202 possessed three fewer tubes for a total EHS of 2,261 sq ft and 203 had 249 tubes and a total EHS of 2,228 sq ft. All had 20 sq ft (1.86 sq m) of arch tubes contributing to the firebox heating surface area. Their slide valves had a 5 1/2" (140 mm) and were actuated by inside link motion..

204 arrived two years later and was sufficiently different to merit a separate entry; see Locobase 16570.

Obviously the class worked out -- possibly because it possessed that very attractive attribute of having been paid for. Unusually, and unlike the identical LS&MS engines procured at the same time (see Locobase 5548), these engines apparently were never superheated. (To see what a superheated version of this design might have looked like, go to Locobase 16386, which describes the very similar 1920 pair of Atlantics delivered to short line Pittsburg & Shawmut in western Pennsylvania.)

When the Wabash absorbed the Ann Arbor, the new owner redesignated the four I class engines as E-5 and renumbered them 1610-1613. 1613 fell to the torch in December 1933. After class leader 1610 wrecked on 30 September 1936, she was scrapped two months later.

Two were retired in the 1930s -- 1 and 1610 in November 1936. Even in February 1950, the class still averaged 279 miles per day per engine, considerably more than any other class.

The other two carried on until 1951 and the end of the steam era with 1612 going in January, 1612 in February, and 1614 in March.

Principal Dimensions by Steve Llanso of Middle Run Media
ClassI-1/E-6I/E-5
Locobase ID16570 7339
RailroadAnn Arbor (AA)Ann Arbor (AA)
CountryUSAUSA
Whyte4-4-24-4-2
Number in Class54
Road Numbers204/1614200-203/1610-1613
GaugeStdStd
Number Built54
BuilderAlco-SchenectadyAlco-Schenectady
Year19071907
Valve GearWalschaertStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)7 / 2.137 / 2.13
Engine Wheelbase (ft / m)25.96 / 7.9125.96 / 7.91
Ratio of driving wheelbase to overall engine wheelbase 0.27 0.27
Overall Wheelbase (engine & tender) (ft / m)59.04 / 1858.96 / 17.97
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)91,500 / 41,50491,500 / 41,504
Engine Weight (lbs / kg)161,300 / 73,165161,300 / 73,165
Tender Loaded Weight (lbs / kg)136,000 / 61,689136,000 / 61,689
Total Engine and Tender Weight (lbs / kg)297,300 / 134,854297,300 / 134,854
Tender Water Capacity (gals / ML)6700 / 25.386700 / 25.38
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)10 / 910 / 9
Minimum weight of rail (calculated) (lb/yd / kg/m)76 / 3876 / 38
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)69 / 175369 / 1753
Boiler Pressure (psi / kPa)200 / 1380200 / 1380
High Pressure Cylinders (dia x stroke) (in / mm)19" x 26" / 483x66019" x 26" / 483x660
Tractive Effort (lbs / kg)23,125 / 10489.3423,125 / 10489.34
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.96 3.96
Heating Ability
Tubes (number - dia) (in / mm)252 - 2" / 51256 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)16 / 4.8816 / 4.88
Firebox Area (sq ft / m2)157 / 14.59157 / 14.59
Grate Area (sq ft / m2)39.10 / 3.6339.10 / 3.63
Evaporative Heating Surface (sq ft / m2)2253 / 209.312286 / 212.37
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)2253 / 209.312286 / 212.37
Evaporative Heating Surface/Cylinder Volume264.13268.00
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation78207820
Same as above plus superheater percentage78207820
Same as above but substitute firebox area for grate area31,40031,400
Power L181928281
Power MT394.76399.05

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