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

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.)