Midwest Central Railroad's oldest locomotive, No. 6, was built by Baldwin in 1891 for the Surry Sussex & Southampton Railway (named after the three counties where it operated) in Virginia. No. 6 is a class 8-18-D Baldwin, meaning it is a 2-6-0 with cylinders bored to 12". It has a cylinder stroke of 18" and has 37" drivers. No. 6 weighs about 25 tons (30 tons with its tender), and was listed as being 37'-1" long by Baldwin on October 1st, 1927.

Originally, No. 6 was built as a wood burner with a straight stack, extended smokebox, box-style kerosene headlight, and a vertical stave pilot. In 1898, No. 6 was converted to burn coal. In 1903, the original headlight was replaced with a 2" smaller box headlight. The headlight was again replaced in 1913, but this time with a round-case, however, the size remained the same. Sometime before 1914, the original Baldwin straight capped stack was replaced with a venturi-shaped cast stack, and the plate pilot wheel replaced with a spoked pilot wheel. Sometime after 1914, No. 6 received many modifications such as Southern Valve Gear (replacing the factory Stephenson Valve Gear), a Pyle-National electrical system, a rear sand-box, a new tender tank, a new smokebox, and a switchyard style pilot.

No. 6 was retired in 1925 when traffic declined at the SS&S. Shortly after the sale, it was purchased back by Baldwin. It was resold by Baldwin on January 11th, 1936, to the Argent Lumber Company in South Carolina. No. 6 went back to burning wood at Argent. At Argent, No. 6 would operate alongside two of what would become the MCRR's other locomotives: N.B.&W.R.R./A.L.Co.'s No. 2 and B.C.L.Co./A.L.Co.'s No. 1 until 1956. At Argent Lumber, No. 6 gained an iron cab and Rushton stack. Various other small details were arranged at Argent's convenience as well, such as the relocation and replacement of the dynamo. In 1955, it suffered a crown-sheet failure that killed the engine crew, but was soon rebuilt.

In 1960, No. 6 was purchased by the Midwest Central Railroad along with the No. 2. It was the first locomotive to operate on the MCRR and was the main engine until 1971 when it was taken out of service for major repairs. No. 6 returned to service in 1988, with a new boiler and conversion to oil fire. No. 6 was out of service from 2008 until 2010 for flue and firebox-stay repairs. The inside cab piping, injectors, and other controls were refined in early 2018.