Boston and Maine No. 3713
B&M No. 3713 on static display at Steamtown, U.S.A.
Type and origin Power type Steam Builder Lima Locomotive Works Serial number 7625 Build date December 1934
Specifications Configuration: ​  • Whyte 4-6-2  • UIC 2′C1′ n2 Gauge 4 ft 8+1⁄2 in (1,435 mm) Driver dia. 80 in (2,032.0 mm) Wheelbase 77 ft 7 in (23.6 m) Adhesive weight 209,500 lb (95,027.6 kilograms; 95.0 tonnes) Loco weight 339,200 lb (153,858.5 kg; 153.9 t) Tender weight 240,800 lb (109,225.0 kg; 109.2 t) Total weight 580,000 lb (263,083.6 kg; 263.1 t) Fuel type Coal Fuel capacity 37,000 lb (16,782.9 kg; 16.8 t) Water cap. 12,000 US gallons (45,000 L; 10,000 imp gal) Firebox: ​  • Grate area 66.9 sq ft (6.22 m2) Boiler pressure 260 psi (1.79 MPa) Feedwater heater Coffin Heating surface: ​  • Firebox 320 sq ft (30 m2)  • Tubes and flues 3,848 sq ft (357.5 m2)  • Total surface 4,814 sq ft (447.2 m2) Superheater: ​  • Heating area 966 sq ft (89.7 m2) Cylinders Two Cylinder size 23 in × 28 in (584 mm × 711 mm) Valve gear Walschaerts Valve type Piston valves
Performance figures Tractive effort 40,918 lbf (182 kN) 52,800 lbf (235 kN) (w/ booster) Factor of adh. 5.12
Career Operators Boston and Maine Railroad (1934–1958) Class P-4a Numbers B&M 3713 Official name "The Constitution" Locale New England Delivered December 21, 1934 Last run April 22, 1956 Retired July 1956 Preserved June 11, 1958 Current owner Steamtown National Historic Site Disposition Undergoing restoration to operating condition
References:[1]

Boston and Maine 3713, also known as the "Constitution", is the sole survivor of the "P-4a" class 4-6-2 "Heavy Pacific" type steam locomotives. It was built in December 1934 by the Lima Locomotive Works for the Boston and Maine Railroad (B&M), hauling passenger trains around the New England region. In 1956, No. 3713 was given the duty to haul B&M's Farewell to Steam excursion between Boston, Massachusetts and Portland, Maine, marking the end of steam operations on the B&M.

Afterwards, the locomotive was purchased by New England millionaire F. Nelson Blount for his Steamtown, U.S.A. collection. After Blount died in 1967, No. 3713 was loaned to the Boston Museum of Science for static display. In 1985, No. 3713 was returned to Steamtown, which had moved to Scranton, Pennsylvania, one year prior.

When Steamtown was nationalized as Steamtown National Historic Site, work began in 1995 to restore No. 3713 to operating condition for use in pulling excursion trains. It was the focus of Project 3713, a partnership between the National Park Service and the Lackawanna & Wyoming Valley Railway Historical Society. As of 2024, restoration work on the No. 3713 locomotive is still ongoing.

No. 3713 was the fourth member of five "P-4a" class heavy 4-6-2 Pacifics (Nos. 3710-3714) ordered by the Boston and Maine (B&M) in December 1934 at the Lima Locomotive Works (LLW) in Lima, Ohio, at a cost of $100,000.^[1] These locomotives were originally built with smoke deflectors, a single air compressor mounted on their pilot deck, and a metal sky-lining shroud covering up the top of their boiler thus giving them a semi-streamlined appearance.^[1] In 1936, the B&M ordered the final batch of five Pacifics (Nos. 3715-3719) which were delivered in March 1937 as the last Pacifics to be built by Lima.^[1] Slightly classified as P-4b, they were delivered with smoke deflectors but without the sky-lining shroud.^[1]

Designed with 80 in (2,032 mm) driving wheels, a larger firebox, and a massive boiler, the P-4 Heavy Pacifics would easily cruise at a speed of 70 miles per hour, carrying enough coal to pull a 14-car train for about 250 miles, and enough water to last about 125 miles.^[1] During World War II, all of the P-4s had their sky-lining shrouds and smoke deflectors removed for easier maintenance.^[1] Around 1944 or 1945, a second air compressor was added on all of the locomotives' pilot deck.^[1] They were assigned to haul B&M's high priority passenger trains such as the Minute Man, Alouette, Red Wing, and Flying Yankee all over the New England states.^[1][2]

The B&M sponsored the New England school students a contest to give all five P-4a and five other P-4b names.^[1] On December 11, 1937, No. 3713 was officially named The Constitution by J. Schumann Moore, a 14-year-old student from Eastern High School in Lynn, Massachusetts.^[1] Between 1940 and 1941, other winning names were selected to P-4a Pacifics No. 3710 as Peter Cooper, No. 3711 as Allagash, No. 3712 as East Wind, and No. 3714 as Greylock.^[1] While the P-4b Pacifics Nos. 3715 to 3719 were also named Kwasind, Rogers’ Rangers, Old North Bridge, Ye Salem Witch, and Camel’s Hump, respectively.^[1] Each locomotive all has a plaque representing the students' name and their respective educated school.^[1]

After being withdrawn from passenger duties by newer diesel locomotives in the mid 1950s, No. 3713 became a stationary boiler to melt the snow and heat the passenger cars at the North Station terminal in Boston, Massachusetts.^[1] It was recalled to road service to cover for diesel locomotives during a flood, presumably in relation with the events of Hurricane Diane which affected the area at that time.^[1] On April 22, 1956, No. 3713 ran the Farewell To Steam excursion round trip between Boston and Portland, Maine, marking the end of steam operations on the B&M, and was officially retired from revenue service in July 1956.^[3][4]

On June 11, 1958, the No. 3713 locomotive was purchased by New England millionaire F. Nelson Blount as part of his Steamtown, U.S.A. collection at the Edaville Railroad in South Carver, Massachusetts, then Pleasure Island park in Wakefield, Massachusetts, before it was moved to North Walpole, New Hampshire in 1961, and finally Bellows Falls, Vermont in 1964.^[1][5] In October 1969, Steamtown put No. 3713 on a long-term loan to the Boston Museum of Science (MoS).^[6][7] The locomotive was moved to the B&M’s shops in Billerica, Massachusetts for a cosmetic restoration, and then it was put on static display outside the MoS’ building.^[6] In February 1985, the MoS decided to end their lease with No. 3713 to allow room for expansion, and the locomotive was moved to Steamtown’s recently-relocated property in Scranton, Pennsylvania.^[7]

Since 1995, the No. 3713 locomotive is currently being restored to operating condition through the Project3713 partnership with the Lackawanna & Wyoming Valley Railway Historical Society (L&WVRHS).^[8] The estimated restoration work cost was $1.4 million, which required repairs to the boiler, air compressors, feedwater heater, and pilot truck.^[8][9] During 2011, the No. 3713 locomotive received new firebox grates, sheets, and thermic siphons, which were fabricated by Diversified Rail Services.^[10][11]

In October 2017, the driving wheels were sent to be repaired by the Strasburg Rail Road (SRC) in Strasburg, Pennsylvania for crankpin and axle work until they returned to Steamtown in spring 2019.^[12][13] In late August 2018, Steamtown gave SRC a $148,600 contract to build a brand new firebox for the No. 3713 locomotive.^[14] In October 2018, No. 3713 received three new safety valves, which were built by the SRC.^[15] In October 2019, the new firebox arrived at Steamtown and installed on the No. 3713 locomotive.^[16] In September 2023, Steamtown's formal partnership with L&WVRHS had ended, and the latter deposited the funds needed for No. 3713 into an account made specifically for the restoration.^[17] Once restored to operating condition, No. 3713 will eventually become the replacement for both Canadian National 3254 and Canadian Pacific 2317.^[8][18]

• 
  No. 3713's tender^[a]
• 
  No. 3713's boiler
• 
  No. 3713's driving wheels at the Strasburg Rail Road workshop in 2017

• Baldwin Locomotive Works 26
• Canadian Pacific 2317
• Nickel Plate Road 759

• Drury, George H. (2015). Guide to North American Steam Locomotives (2nd ed.). Kalmbach Media. ISBN 978-1-62700-259-2.
• Heald, Bruce D. (2001). Boston and Maine in the 20th Century. Images of Rail (1st ed.). Arcadia Publishing. ISBN 0-7385-0547-1.
• McLaughlin, Robert (2009). Pleasure Island. Images of America (1st ed.). Arcadia Publishing. ISBN 978-0-7385-6460-9.

• Frye, Harry A. (1982). Minuteman Steam: Boston & Maine Steam Locomotives, 1911-1958 (1st ed.). Boston and Maine Railroad Historical Society. ISBN 0-916578-04-6.

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