Southern Railway 4501

Specifications
Specifications
Configuration:;
• Whyte	2-8-2
• UIC	1'D1'h
Gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Driver dia.	63 in (1,600 mm)
Adhesive weight	215,700 lb (97,800 kg)
Loco weight	272,900 lb (123,800 kg)
Fuel type	Coal
Fuel capacity	Old tender: 12 t (12 long tons; 13 short tons) ; New tender: 16 t (16 long tons; 18 short tons), formerly 18 t (18 long tons; 20 short tons)
Water cap.	Old tender: 8,000 US gal (30,000 L; 6,700 imp gal); New tender: 13,000 US gal (49,000 L; 11,000 imp gal), formerly 12,500 US gal (47,000 L; 10,400 imp gal) and 13,400 US gal (51,000 L; 11,200 imp gal)
Boiler pressure	205 psi (1.41 MPa), formerly 200 psi (1.38 MPa)
Feedwater heater	Worthington SA (added during its 2012-2014 overhaul)
Cylinders	Two, outside
Cylinder size	27 in × 30 in (686 mm × 762 mm)
Valve gear	Walschaerts

Type and origin
Type and origin
Power type	Steam
Builder	Baldwin Locomotive Works
Serial number	37085
Model	12-48 1/4 E
Build date	October 1911
Rebuilder	Southern Railway
Rebuild date	1940s

Southern Railway 4501
Southern Railway 4501
	Southern Railway No. 4501 idling at Summerville, Georgia, during an excursion layover, November 3, 2024
Power type
Type and origin
Power type	Steam
Builder	Baldwin Locomotive Works
Serial number	37085
Model	12-48 1/4 E
Build date	October 1911
Rebuilder	Southern Railway
Rebuild date	1940s
Configuration:;
Specifications
Configuration:;
• Whyte	2-8-2
• UIC	1'D1'h
Gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Driver dia.	63 in (1,600 mm)
Adhesive weight	215,700 lb (97,800 kg)
Loco weight	272,900 lb (123,800 kg)
Fuel type	Coal
Fuel capacity	Old tender: 12 t (12 long tons; 13 short tons) ; New tender: 16 t (16 long tons; 18 short tons), formerly 18 t (18 long tons; 20 short tons)
Water cap.	Old tender: 8,000 US gal (30,000 L; 6,700 imp gal); New tender: 13,000 US gal (49,000 L; 11,000 imp gal), formerly 12,500 US gal (47,000 L; 10,400 imp gal) and 13,400 US gal (51,000 L; 11,200 imp gal)
Boiler pressure	205 psi (1.41 MPa), formerly 200 psi (1.38 MPa)
Feedwater heater	Worthington SA (added during its 2012-2014 overhaul)
Cylinders	Two, outside
Cylinder size	27 in × 30 in (686 mm × 762 mm)
Valve gear	Walschaerts
Power output
Performance figures
Power output	2,700 hp
Tractive effort	53,900 lbf (239.8 kN)
Factor of adh.	4.00
Operators
Career
Operators	Southern Railway; Kentucky and Tennessee Railway; Norfolk Southern Railway; Tennessee Valley Railroad Museum;
Class	Ms
Number in class	1st of 182
Numbers	SOU 4501; K&T 12;
Nicknames	The Big Engine (by K&T crews); The Green Mikado;
Retired	July 1948 (1st revenue service); February 1964 (2nd revenue service); June 7, 1964 (1st excursion service); September 20, 1998 (2nd excursion service);
Restored	October 7, 1948 (1st revenue service); June 6, 1964 (2nd revenue service); August 1966 (1st excursion service); September 6, 2014 (2nd excursion service);
Current owner	Tennessee Valley Railroad Museum
Disposition	Operational
	Reference:
	Mikado Locomotive No. 4501
	U.S. National Register of Historic Places
Location	2202 N. Chamberlain Ave., Chattanooga, Tennessee
Coordinates	35°3′43″N 85°15′1″W / 35.06194°N 85.25028°W
Built	1911
Built by	Baldwin Locomotive Works
NRHP reference No.	79002440
Added to NRHP	March 28, 1979

Southern Railway 4501 is a preserved 2-8-2 "Mikado" type steam locomotive. Built in October 1911 by the Baldwin Locomotive Works (BLW) in Philadelphia, Pennsylvania, No. 4501 was the first of its wheel arrangement type for the Southern Railway (SOU). It was assigned to pull freight trains on the SOU system until 1948, when it was retired from revenue service in favor of dieselization and was subsequently sold to the shortline Kentucky and Tennessee Railway (K&T) in Stearns, Kentucky, to haul coal trains.

When the K&T was dieselized in 1964, No. 4501 was purchased by a railfan named Paul Merriman for $5,000 of his own money, and he brought it to Chattanooga, Tennessee. Shortly thereafter, it was returned to service for main line excursion service on the Southern's steam program started by the company's president, W. Graham Claytor Jr. in 1966 through Merriman's 4501 Corporation.

Repainted in SOU's passenger Virginian green and gold paint scheme, No. 4501 operated as the primary excursion attraction of Southern's steam program, until it was replaced with larger locomotives in 1985. In 1991, the locomotive returned to mainline excursion service, but in 1994, it was removed again when the SOU's successor, Norfolk Southern (NS), discontinued the steam program due to rising insurance costs and decreasing rail network availability.

No. 4501 then continued to operate for the Tennessee Valley Railroad Museum (TVRM) in Chattanooga. Merriman was a founding member of the TVRM, and had donated No. 4501 from his personal property to the museum in 1975. Repainted into its original freight black livery in 1996, the locomotive was retired when its boiler ticket certificate expired in 1998.

In 2012, following the start of Norfolk Southern's 21st Century Steam Program and the success of the TVRM's Southern Railway 630's return to service, restoration work on No. 4501 began, with upgrades such as a feedwater heater and mechanical stoker. No. 4501's restoration was completed in 2014. As of 2026, the locomotive operates in tourist excursion service at TVRM, particularly on their Missionary Ridge Local and Evening Ridge Runner weekend excursions if needed and longer trips such as the Summerville Steam Special to Summerville, Georgia.