Southern Railway 4501 is a preserved Ms class 2-8-2 "Mikado" type steam locomotive.

4501 was purchased by a railfan named Paul Merriman for $5,000 of his own money, and he brought it to Chattanooga, Tennessee.

Repainted into its original freight black livery in 1996, the locomotive was retired when its boiler ticket certificate expired in 1998.

4501 operates in tourist excursion service at TVRM, traditionally on the longer special trips to Summerville, Georgia, throughout the year and TVRM's Missionary Ridge Local and Evening Ridge Runner excursions as needed during the weekends.

[3][4] They were designed with 63 in (1,600 mm) diameter driving wheels and an operating boiler pressure of 200 psi (1.38 MPa), and they were able to generate 53,900 lb (24.4 tonnes) of tractive effort.

[2][8] It was assigned to haul freight trains on many different divisions of the SOU system in Tennessee, Virginia, Kentucky, and Indiana.

12 worked on the K&T hauling coal trains until February 1964, when the K&T purchased three ALCO S-2 diesel locomotives from the Denver and Rio Grande Western.

4501 moved under its own power to Chattanooga from the K&T, an initial restoration was undergone by Tennessee Valley Railroad Museum (TVRM) volunteers at the facilities of the Lucey Boiler Company in Chattanooga near the TVRM's storage facilities, which were at the time located on former Western Union Company trackage.

4501 was disassembled for an extensive overhaul, with the thin cab floor, the rotted ash pan, and the rusty smokebox front replaced.

[10] The cylinder cocks were reworked, and the throttle was lapped with a new air line run to the repacked reversing gear.

[15][16] Additionally, it carried 18 tonnes (18,000 kg) of coal and 12,500 US gallons (47,000 L) of water, which significantly improved the locomotive's range and allowed it to accommodate longer distance runs.

[14][a] In November that same year, during the 75th anniversary of the Southern Railway, an event called the Steam-O-Rama took place in Anniston, Alabama, on the Birmingham-Atlanta mainline.

[18] Throughout the summer of 1973, at the request of Trains magazine editor David P. Morgan and officials from the Chicago and North Western (C&NW), No.

4501 operated outside of Southern Railway property to pull a series of excursion trips in the Midwestern United States on trackage owned by the C&NW, the Milwaukee Road (MILW), the Illinois Central (IC), the Rock Island (RI), and the Norfolk and Western (N&W).

4501 travelled from Durham, North Carolina to Roanoke, Virginia, to participate in that year's NRHS Convention.

4501 pulled eleven cars solo on the SOU main line to Altavista, and then it returned to Roanoke via N&W's former Virginian trackage.

[2] On April 11, 1981, the locomotive suffered a cracked front flue sheet at Dalton, Georgia, while pulling an excursion trip from Atlanta to Chattanooga.

4501 was towed back to the Irondale Workshop in Birmingham, Alabama, for a long-term rebuild, lasting until November 1984.

[30] At the end of the 1985 operating season, the locomotive was retired from mainline excursion service and moved back to the TVRM due to SOU's successor, Norfolk Southern (NS), expanding the steam program with larger N&W locomotives, 4-8-4 J class No.

4501 was pulling an NS mainline excursion trip on April 30, 1994, planned to be from Birmingham to Columbus, Georgia.

[35][36] In October that same year, NS executives announced that they would discontinue their steam program due to serious safety concerns, rising insurance costs, the expense of maintaining steam locomotives, and decreasing rail network availability due to a surge in freight traffic.

[38][39] Beginning in October 1995, when its repairs were completed, it solely hauled the museum's excursion trains through north Georgia on the Chattooga and Chickamauga Railway shortline.

[38][39] In October 1996, the locomotive was repainted back to its original freight black livery for TVRM's 35th anniversary.

630 returned to service pulling tourist trains for the TVRM and some of the first mainline excursion trips for the new steam program.

[45] A Worthington SA type feedwater heater replica from a China Railways QJ Class 2-10-2 was installed on No.

[45] Its tender received a mechanical stoker from Canadian National 5288, a 4-6-2 steam locomotive that was also on display at TVRM, but would later be sold to the Colebrookdale Railroad in 2023.

[49][50][51] The locomotive made a test run from Chattanooga to LaFayette, Georgia, on the Chattooga and Chickamauga Railway line on September 25, in preparation for TVRM's upcoming annual Summerville Steam Special on October 4 that year.

4501 returned to the Norfolk Southern main line for the first time in 21 years and successfully completed a test round trip from TVRM to Cleveland, Tennessee.

[56] Two weeks later, the locomotive pulled the Nancy Hanks Special excursion from Macon to Tennille, Georgia.

4501 was planned to run the Piedmont Limited round trip excursion from Atlanta to Toccoa, Georgia, on October 3 and 4, 2015, but it was canceled on October 1 due to Hurricane Joaquin, making the locomotive's career for the 21st Century Steam program short-lived.