Tremont and Gulf 30

As the United States entered World War I, railroads across the nation faced a larger demand for larger and more powerful locomotives, and the Louisiana-based Tremont and Gulf Railroad (T&G) was no exception. Thus, in 1917, the T&G created a new design of a 2-8-2 "Mikado" type and ordered it from the Baldwin Locomotive Works of Philadelphia, Pennsylvania, and it was built and delivered in October of that year as No. 30.[1] This new locomotive proved to be a more powerful unit than any of its predecessors,[2] as it was capable of producing over 36,000 pounds of tractive effort, it had a boiler pressure of 185 pounds per square inch, it had superheaters with eleven inch piston valves, and it had a driver diameter of 54 inches. It wasn't suitable for mainline operations, but still a large enough size for small, basic-material sized shortlines like the T&G, and No. 30 was the largest locomotive the T&G has ever owned. An unusual detail for a late 1910s-built model was that the two sand domes and the lone steam dome had collars on both their bases and their tops, which gave the locomotive a 19th-century touch. No. 30 was used by the T&G to haul oil and lumber around the T&G system, particularly between Tremont, Winnfield, and West Monroe. As the 1950s began to progress, however, the T&G became one of many American railroads that decided to dieselize early on, and by 1954, all of their steam locomotives were withdrawn and sold off.

That year, No. 30 was purchased by another shortline railroad, the Magma Arizona Railroad (MAA).[1] The locomotive then made its way to Magma, Arizona, where it was given another overhaul, and it was renumbered 7, as it was the seventh locomotive the MAA has ever acquired. The locomotive's new assignment was to haul copper, minerals, and local freight trains across the MAA system, particularly between the copper mines and towns of Florence and Queen Creek. No. 7 was also the most reliable unit of the roster when it came to running out of hills, such as the grade between Desert Well and the MAA-Southern Pacific interchange in Magma. Although, 2-8-0 No. 5 was the MAA's most powerful steamer. After serving the T&G for thirty-seven years and serving the MAA for an additional fourteen years, No. 7 completed its last revenue freight assignment on September 4, 1968, making it surpass Denver and Rio Grande Western K-36 locomotives Numbers 483 and 484 as the last common carrier steam locomotive to be used in revenue service in the Southwestern United States by over a month.[3] Afterwards, No. 7 was sold to Steve Bogen in 1969, who, in turn, donated it to Trans North of Superior, Arizona in 1972.

Upon arrival of Superior, No. 7 faced a future where it would remain as a static display piece. In 1974, however, the locomotive was purchased again by, the Texas Parks and Wildlife Department, the early founders of the Texas State Railroad (TSRR).[4] No. 7 was only one of five steam locomotives the group had purchased and wanted to restore to operating condition as part of their efforts to reopen the TSRR as a tourist railroad. It was shipped by rail to Hahn and Clay in Houston, Texas to be rebuilt and refurbished by a group of volunteers. Boiler men, welders, and technicians took four years to repaint, repair, and replace components of the locomotive. When restoration work was almost completed, a new plate was made with the words "Rebuilt by Hahn & Clay Houston, Texas for the Texas Parks and Wildlife Department, Steam Locomotive No. 400, Type 2-8-2, Job No. 20078, State of Texas contract No. 09347, 1977–1978". During this process, the locomotive was also renumbered 400, since the TSRR decided to number their locomotives in order of size by hundreds.[5] In March 1978, the locomotive was moved to its new home base of Rusk, where it was fired up for the first time in less than ten years.[6]

The locomotive began being used to pulling tourist trains between Rusk and Palestine almost every year alongside other restored locomotives, including Texas and Pacific 4-6-0 "Ten-wheeler" No. 316(No. 201), 2-8-0 "Consolidation" No. 28(No. 300), Atchison, Topeka and Santa Fe 4-6-2 "Pacific" No. 1316(No. 500), and RS-2 diesel switcher No. 7.[7] It would also perform occasional doubleheaders with some of its running mates.[8] In 1996, No. 400 took part in the centennial of the TSRR historical park, and since then, it was one of the TSRR's five steam locomotives to be featured in one of their 'symbols'.[9][10] Since 1995, however, the Federal Railroad Administration (FRA) has ordered that every active steam locomotive be inspected and overhauled every 1,472 days.[11] This new regulation forced No. 400 to be sidelined after making its final run as No. 400 on June 22, 2002.[12][13] No. 400 subsequently spent the next twelve years sitting idle just outside the locomotive facility in Rusk.[14]

In 2012, Iowa Pacific Holdings gained ownership of the TSRR, and they decided to have a group of volunteers finish the restoration of No. 400 to have it running again, since No. 201's flue time was close to expiring, and the railroad needed to keep a second steam locomotive on their active roster alongside No. 300.[15][16] Iowa Pacific also decided to revert all of their steam locomotives to their original revenue liveries, instead of leaving them in their TSRR colors. As a result of this decision, when No. 400 was brought back under steam in April 2014, it was reverted to one of its older appearances as Magma Arizona No. 7. In July 2016, No. 7 took part in a photographer's special alongside No. 28, and the two locomotives would perform a few doubleheaders.[17] In early 2017, ownership of the TSRR was moved again to the Western Group, and No. 7 was reverted to its older appearance as Tremont and Gulf No. 30. The locomotive would also be one of the one that would pull and push Texas and Pacific 2-10-4 "Texas" type No. 610 in and out of the engine house at Palestine.[18] As of 2023, No. 30 is still being used for tourist operations on the TSRR alongside No. 28.[19] Its next 1,472-day inspection will likely take place in 2029, as that will have marked fifteen years since No. 30's 2014 return.