In 1937, the ACL received 12 new Class R-1 4-8-4s from the Baldwin Locomotive Works. They were assigned road numbers 1800 through 1811 and were immediately put into passenger service. These new 4-8-4s began to handle trains with as many as 21 heavyweight cars, eliminating the need for double-heading and running extra sections of many of the Richmond, VA to Jacksonville, FL "Specials".
The ACL was very disappointed with their R-1s, and returned them to Baldwin for better counterbalancing of the 80 inch drive wheels. It seems the R-1s, as delivered, had a bad dynamic augment. It was so bad that it was even worse than the Norfolk & Western's J class 4-8-4s with their low 70 inch drive wheels. Even after Baldwin checked their math, and put new disk drivers on the ACL R-1s, they still had unacceptable amounts of dynamic augment at high speeds. As soon as the ACL could replace them with EMD E-3 and E-6 diesel electrics, the Standard Railroad of the South put its latest and largest steamers in freight service.
Originally built by Great Northern with relatively tall drivers for a compound articulated. They presented an imposing appearance, showing a high Belpaire boiler over ten axles of running gear. Firebox heating surface included 81 sq ft (7.53 sq m) of combustion chamber, which was separated from the main firebox by a brick half wall. All four cylinders were fed through 15" (381 mm) piston valves.
The engines were big and superheated and presumably presented some new challenges. So the specs contain some "Hereafter" notes tweaking details. One, however, implied a higher level of urgency. Referring to a letter from F A Neely received on 3 November 1912, the note said "Give particular attention to riveting of cylinder saddles and caulking of same."
"Leaky seams" forced the railroad to remove lagging from all the boilers in the first batch save that of 2016 and caulk them. A least some high-pressure cylinders leaked and the flexible stay bolts at the back end of the combustion chamber either required redesign or at least more stays. (The firebox had 900 Tate flexible staybolts in all as well as 200 Tate expansion staybolts on the entire roof of the combustion chamber.)
The N-1s were simpled in the 1920s, becoming N-2s and later N-3s in the process (Locobases 2802 and 6445, respectively).
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Atlantic Coast Line (ACL)|
|Number in Class||12|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.43|
|Overall Wheelbase (engine & tender)||97.92'|
|Axle Loading (Maximum Weight per Axle)||65792 lbs|
|Weight on Drivers||263127 lbs|
|Engine Weight||460270 lbs|
|Tender Light Weight||435000 lbs|
|Total Engine and Tender Weight||895270 lbs|
|Tender Water Capacity||24000 gals|
|Tender Fuel Capacity (oil/coal)||27 tons|
|Minimum weight of rail (calculated)||110 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||275 psi|
|Cylinders (dia x stroke)||27" x 30"|
|Tractive Effort||63901 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.12|
|Firebox Area||568 sq. ft|
|Grate Area||97.75 sq. ft|
|Evaporative Heating Surface||4753 sq. ft|
|Superheating Surface||1425 sq. ft|
|Combined Heating Surface||6178 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||239.08|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||26881|
|Same as above plus superheater percentage||33064|
|Same as above but substitute firebox area for grate area||192126|