Warner's smaller boiler is that of the Harriman Common Atlantic design, which Drury (1993) says was the source of this quartet's dimensions. But data from a table in July 1904 American Engineer & Railroad Journal shows a bigger engine in all respects except weights, which are actually a bit lower than the HCS. For example, the boiler was credited with 326 2 1/4" tubes and a total evaporative heating surface of 3,247 sq ft.
The 1918 C&A diagrams show 278, which undoubtedly reflects the installation of a new boiler at a later date. Locobase chose the larger boiler dimensions for the specifications when he found those figures in John M Burley's First Aid to the Disabled Locomotive Engine, Air Brake and Air Signal (State Line, Pa, 1907), 140-143.
Locobase doesn't know when the Alton reduced the number of tubes in the boiler or why. A boiler smaller than 69" in diameter crammed with 326 2 1/4" tubes might have proved a maintenance headache. When the Alton superheated this set (Locobase 9040), it installed fewer tubes of 2" diameter. The class was delivered with 12" piston valves.
The answer appears to be as follows: 551 used the HCS grate while the other three were fitted with the larger grate shown in the specs. As the engines were procured around the time that Harriman surrendered control of the C & A, Locobase wonders if the confusion lies in mistakenly attributing these locomotives to the Harriman era.
See Locobase 9040 for the superheated update of this design.
The Alton superheated its quartet of Atlantics with the usual mixture of status quo and new technology and added an unusual wrinkle. As with most modification programs in which a superheater was installed in an existing locomotive, the biggest changes came in the boiler. In this case, the usual subtraction of tubes in favor of flues included reducing the diameter of the remaining tubes from 2 1/4" to 2". Also, the Alton trimmed the firebox's width by 6", reducing grate area to 49 1/2 sq ft, but added 29 sq ft of arch tubes to the firebox's heating surface. In other words, the shops replaced all of the boiler's innards, which is more drastic surgery than usually undertaken.
Regardless of the length and complexity of the makeover, the class was out of service by the end of 1933.
Whatever the design features of the first set of Alton Atlantics might have been (see Locobase 4096), the second group from the same builder had a smaller boiler with smaller tubes and a much narrower grate. The class was delivered with 12" (305 mm) piston valves.
When delivered, these engines trailed tenders with the capacities as shown. Coal capacity later rose to 14 tons (12.7 tonnes) and the loaded tenders weighed 171,250 lb (77,678 kg).
At least three were superheated; see Locobase 9042.
Compared to the nearly complete redo applied to the E-1s (see Locobase 9040), the E-2 superheating project ran along much more usual lines. The firebox remained essentially untouched (although the firebox heating surface now included 15 sq ft of arch tubes) while the boiler saw the usual substitution of 1 flue for every 6 tubes removed.
The result was still a small Atlantic and given the arrangement's relatively swift supercession in fast passenger service by 4-6-2s and their inaptitude for any other kind of hauling, the class was retired by the end of 1933.
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Class||E1||E1 - superheated||E2||E2 - superheated|
|Railroad||Chicago & Alton (C&A)||Chicago & Alton (C&A)||Chicago & Alton (C&A)||Chicago & Alton (C&A)|
|Number in Class||4||4||5||3|
|Road Numbers||550-553||550-553||554-558||554, 556, 557|
|Builder||Burnham, Williams & Co||C & A||Burnham, Williams & Co||C & A|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||7.67 / 2.34||7.67 / 2.34||7.67 / 2.34||7.67 / 2.34|
|Engine Wheelbase (ft / m)||27 / 8.23||27 / 8.23||27 / 8.23||27 / 8.23|
|Ratio of driving wheelbase to overall engine wheebase||0.28||0.28||0.28||0.28|
|Overall Wheelbase (engine & tender) (ft / m)||56.29 / 17.16||56.29 / 17.16||56.17 / 17.12||58.17 / 17.73|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||48,180 / 21,854||58,400 / 26,490|
|Weight on Drivers (lbs / kg)||103,690 / 47,033||96,280 / 43,672||98,000 / 44,452||114,400 / 51,891|
|Engine Weight (lbs / kg)||183,820 / 83,379||184,470 / 83,674||185,000 / 83,915||194,000 / 87,997|
|Tender Loaded Weight (lbs / kg)||171,350 / 77,723||171,250 / 77,678||162,000 / 73,482||171,250 / 77,678|
|Total Engine and Tender Weight (lbs / kg)||355,170 / 161,102||355,720 / 161,352||347,000 / 157,397||365,250 / 165,675|
|Tender Water Capacity (gals / ML)||6000 / 22.73||9000 / 34.09||9000 / 34.09||9000 / 34.09|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||14 / 12.70||14 / 12.70||10 / 9.10||14 / 12.70|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||86 / 43||80 / 40||82 / 41||95 / 47.50|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||80 / 2032||80 / 2032||80 / 2032||80 / 2032|
|Boiler Pressure (psi / kPa)||200 / 13.80||200 / 13.80||200 / 13.80||200 / 13.80|
|High Pressure Cylinders (dia x stroke) (in / mm)||20" x 28" / 508x711||20" x 28" / 508x711||20" x 28" / 508x711||20" x 28" / 508x711|
|Tractive Effort (lbs / kg)||23,800 / 10795.51||23,800 / 10795.51||23,800 / 10795.51||23,800 / 10795.51|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.36||4.05||4.12||4.81|
|Firebox Area (sq ft / m2)||192.50 / 17.89||221.50 / 20.59||193 / 17.93||208 / 19.33|
|Grate Area (sq ft / m2)||54.20 / 5.04||49.50 / 4.60||33.60 / 3.12||33.60 / 3.12|
|Evaporative Heating Surface (sq ft / m2)||3247 / 301.77||2302 / 213.94||2700 / 250.84||2002 / 186.06|
|Superheating Surface (sq ft / m2)||507 / 47.12||507 / 47.12|
|Combined Heating Surface (sq ft / m2)||3247 / 301.77||2809 / 261.06||2700 / 250.84||2509 / 233.18|
|Evaporative Heating Surface/Cylinder Volume||318.92||226.11||265.20||196.64|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||10,840||9900||6720||6720|
|Same as above plus superheater percentage||10,840||11,682||6720||8064|
|Same as above but substitute firebox area for grate area||38,500||52,274||38,600||49,920|