CLASS R-2 and R-3 4-8-2

R-2 3500 was the precursor of twenty additional high horsepower Mountain type engines of similar design. All twenty-one were built by Schenectady starting with 3500 in 1924, 7 additional R-2's in 1926 distiguished by high boiler pressure (3501-07), three R-3's with three cylinders in 1926 (3550-52) and ten more in 1928 (3553-62). All were equipped with water-tube fireboxes which were not successful and soon replaced.

R-2 Class

3500 is in Chicago in June 1925 to display her water-tube firebox at the convention of the Mechanical Division of the ARA.

3500 with a shelter for testing engineers.

The cabin housed an instrument which diagrammed steam pressure in the cylinders which was used to calculate horsepower.

3500 with a Vanderbuilt tender at Cedar Hill in May 1938.

R-2-a Class

3501 at Cedar Hill July 1938.

3504 with air compressors on the pilot deck at Southampton Street in July 1939.

3502 has received Baker valve gear and a new front-end throttle location eliminating the need for the slanting steam admission pipes.

3503 at Sharon Summit with BO-1 in 1940. Air tank has been removed to accomodate the new Walschaert valve gear.

R-2-a 3507 at Cedar Hill.

R-3 and R-3-a were built in 1926 and 1928 respectively.

R-3 3550 and R-3-a 3556

The front-end throttle on 3556 is below the superheater instead of in front of the stack and allows a straight steam admission pipe.

3550 is westbound near Danbury August 28, 1937.

R-3 3552 with an R-1-b at Readville on the way to Southampton Street November 1937. Photo by Charles Brown.

3553 when new.

R-3-a 3554 with relocated air compressors

3554 at Cedar Hill

R-3-a 3556 at Cedar Hill April 1938

R-3-a 3559 being washed at Southampton Street in June 1938.

R-3 3551 at Cedar Hill May 1920.

R-3-a 3553 has air compressors behind the shield mounted sideways to accomodate the Gresley valve gear. Boston August 1940.

R-3-a 3554 has no air compressor shield.

R-3-a 3555 westbound near Branford February 1939

R-3 3551 eastbound near Northford March 1941.

3558 at Maybrook powering a fan trip in September 1937. An R-3-a with a passenger train was rare.

3561 at Worcester in 1945 by H. W. Pontin.