|Type and origin|
|Gauge||4 ft 8 1⁄2 in (1,435 mm)|
|36 in (914 mm)|
|Driver diameter||80 in (2,032 mm)|
|50 in (1,270 mm)|
|Wheelbase||13 ft 10 in (4.2 m) between driving axles|
|Length||83 ft 6 in (25.5 m)|
|Locomotive weight||274,500 lb (124,511 kg)|
|Boiler pressure||205 psi (1,413 kPa)|
|Firegrate area||70 sq ft (7 m2)|
|Cylinder size||27 in × 28 in (686 mm × 711 mm)|
|Tractive effort||44,460 lbf (197,767.9 N)|
|Official name||Passenger Locomotive No. 1737|
|Designated||December 17, 1979|
|Part of||Pennsylvania Railroad Rolling Stock Thematic Resource|
PRR 3750 is a Pennsylvania Railroad K4s steam locomotive located in the Railroad Museum of Pennsylvania, outside of Strasburg, Pennsylvania in the United States. For over a decade, 3750 stood in for the prototype K4s, 1737, and was listed on the National Register of Historic Places in 1979. It is one of the two remaining K4s locomotives and, along with PRR 1361, was designated the official state steam locomotive in 1987 by the Pennsylvania General Assembly.
PRR 3750 was used to haul the Pennsylvania Railroad's main line passenger trains such as the Broadway Limited. Despite the attempt by railroad management to replace the K4s with the K5 and T1, the K4s would remain in action until dieselization in 1957. The 3750 was spared from being scrapped because, when the Pennsylvania Railroad was considering steam engines for preservation, the first K4, 1737, had deteriorated to the point that it was not worth preserving. The Pennsylvania decided to scrap 1737 and use 3750 as a stand-in; 3750 received the original number plates and tender from 1737.
The Pennsylvania General Assembly designated 3750 and 1361 the official state steam locomotives on December 18, 1987, while also designating the GG1 4859 the state electric locomotive in the same bill.
- List of Pennsylvania state symbols
- National Register of Historic Places listings in Lancaster County, Pennsylvania
- "NPS Focus". National Register of Historic Places. National Park Service. Retrieved July 27, 2013.
- Pennsylvania Railroad Rolling Stock 1978, sec. 7, p. 9.
- Alexander, Larry (February 29, 2000). "Full steam ahead; Railroad Museum explores presidential ties". Intelligencer Journal (Lancaster, Pennsylvania). p. B1.
- Act of Dec. 18, 1987, P.L. 421, No. 89.
- "Pennsylvania Railroad Rolling Stock Thematic Resource" (PDF). National Register of Historic Places Inventory—Nomination Form. National Park Service. March 1978. Retrieved July 27, 2013.