Atlantic Coast Line 4-8-4 "Northern" Locomotives of the USA

Because of the growth of Florida tourism in the 1930s, the Atlantic Coast Line was experiencing a surge in its passenger business. To handle this heavy traffic, many of the main line trains were powered by 4-6-2 Pacifics pulling no more than 12 to 14 cars.

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.

Class Details by Steve Llanso of Sweat House Media

Class R-1 (Locobase 238)

Data from 1947 Locomotive Cyclopedia tables and ACL locomotive diagram books supplied in May 2005 by Allen Stanley from his extensive collection . See also "4-8-4 Type Locomotives for the Atlantic Coast Line", Baldwin Locomotives, Volume 17, No 1 (July 1938), pp. 3-7; and "Test Run of Atlantic Coast Line No. 1800," Baldwin Locomotives, Volume 17, No 3-4 (February 1939), pp. 18-20. Baldwin produced the class in two batches: works numbers 62174-62179 in March 1938 and 62180-62185 in May 1938.

Firebox was loaded with supplemental heating surface. In addition to the firebox area of 272 sq ft (25.27 sq m), R-1s had 127 sq ft (11.8 sq m) in the combustion chamber and 168 sq ft (15.61 sq m) in thermic syphons in both the firebox and combustion chamber. Water entered the boiler through a single Nathan injector with a 10,000 US gallon (37,850 litre) capacity. It was preheated to 220 deg F (104 deg C) by a Worthington open type 5 1/2 SA feed water heater.

Baldwin conducted tests of the 1800 in preparation of the 1938-1939 winter season. The locomotive hauled the Havana Special No. 76, a 20-car, 1,500-ton (1,363 tonne) train over a 648-mile (1,043 km) route from Jacksonville to Richmond. The report published a few months later is a detailed profile of final-stage, top-of-the-line North American steam locomotive design in which boiler performance achieved startling levels in a full-throttle setting with steam cut-offs "as short as consistent with the desired speed".

Average speed was 53.8 mph (86.6 kph) and accelerations to "cruise" speed were quicker than the builder had projected. For example, average time for the 1800 to reach the 60 mph mark was 6.5 minutes and average distance was 5.3 miles. To continue accelerating to 70 mph took another 5 minutes (to 11.5 minutes) and 5.7 miles (to 11 miles). The latter level had been projected to take 21.67 minutes and 20 miles and Baldwin was delighted to report the nearly 50% greater rate of increase.. (Locobase notes that in all vehicles--whether ship, aircraft, cars or locomotives--gaining that last increment is often requires as much or more output than the first 80-90%.)

All the usual methods for generating massive amounts of very hot steam (substantial additions to direct heating surface area using syphons and combustion chambers, feed water heaters, copious amounts of superheater area) were supplemented by a change in the front-end drafting arrangement that lowered the exhaust stand and installed a six-point star nozzle. Working at maximum speed, steam temperature reached 700 deg F (371 deg C, 463 deg (239 deg C) higher than the maximum 237 deg F (114 deg C) water that emerged from the feed water heater. During the test, the 1800 averaged 73.6 mph (118.5 kph) over a 13 mile stretch and covered 5 miles on a section north of Benson, NC at an average of 84 mph (135 kph).

Baldwin reported that the engine "steamed perfectly". Measurements showed that back pressures when accelerating averaged 15 psi (1.03 bar) and once at running speed dropped to 6 psi (0.41 bar). Front end temperatures averaged 60 deg (15.6 deg C) lower than the steam temperature, "which indicates good combustion and drafting" and a fire that "burned uniformly with a full clear stack." The fire was "cleaned twice during the run, but very little ash came through the grate." The front-end changes were deemed so satisfactory that the other locomotives were modified accordingly.

The R-1s had all the latest features including one-piece cast-steel frame and roller bearings on the driving axles. But Baldwin initially overestimated the amount of counterbalancing these engines required, which led to pounding at high speeds. In fact, says, at high speed ""...the main drivers actually left the rails and repeatedly slammed back down, kinking rails and damaging track alignment for miles."" It took time, but eventually the solution was found in reducing the counterbalancing.

Six of the class (1800-1801, 1806-1809) ran even more smoothly once they were fitted with lightweight pistons by Timken, piston rods, cross heads, and, probably most important, tapered main rods with roller bearing wrist pins.

One source claimed that these engines easily hit 90 mph in passenger service and probably topped 100 at times. In fast freight service, an 1800 was rated at 6,200 tons on the Richmond-Jacksonville main line.

Don Ball (Portrait of the Rails, 1972) says: ""An engine I regret never having seen ...This Baldwin, judging from photos, had to be about the most handsome steam power in the south."" Retired in 1951-1952.

(Note: The ACL never bought 4-8-2s for itself. The only Mountains that ever ran were the five ex-Delaware, Lackawanna & Western 1401s (Locobase 5731) procured in 1943 to address the motive power shortage affecting most US railroads in the middle of World War II. Two others came from the Atlanta, Birmingham & Coast (Locobase 1348) when the ACL absorbed that line in 1946.)

Specifications by Steve Llanso of Sweat House Media
Locobase ID238
RailroadAtlantic Coast Line (ACL)
Number in Class12
Road Numbers1800-1811
Number Built12
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase20.75'
Engine Wheelbase47.75'
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 Drivers263127 lbs
Engine Weight460270 lbs
Tender Light Weight435000 lbs
Total Engine and Tender Weight895270 lbs
Tender Water Capacity24000 gals
Tender Fuel Capacity (oil/coal)27 tons
Minimum weight of rail (calculated)110 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter80"
Boiler Pressure275 psi
Cylinders (dia x stroke)27" x 30"
Tractive Effort63901 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.12
Heating Ability
Firebox Area568 sq. ft
Grate Area97.75 sq. ft
Evaporative Heating Surface4753 sq. ft
Superheating Surface1425 sq. ft
Combined Heating Surface6178 sq. ft
Evaporative Heating Surface/Cylinder Volume239.08
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation26881
Same as above plus superheater percentage33064
Same as above but substitute firebox area for grate area192126
Power L137658
Power MT1262.08



If you have any railroad data such as diagram books, rail station plans or anything else that you would be willing to share, please contact us.