In 1945-1947 the Reading (later absorbed into Conrail, now Norfolk Southern) built thirty class T-1 4-8-4s in its own Reading Shops with boilers lengthened from class I-10sa 2-8-0s. Nos. 2100-2129, intended for freight service, had 70-inch drivers, 27x32-inch cylinders, 240 p.s.i. of boiler pressure, and a locomotive weight of 441,300 pounds. They exerted 68,000 pounds of tractive effort, which was augmented to 79,100 pounds with the booster operating. Their wide firebox, with 95 square feet of grate area, was typical of the Reading's locomotives. Originally it enabled them to use the cleaner-burning anthracite coal mined in eastern Pennsylvania, but by the time the T-1s were built the Reading's locomotives were burning regular bituminous coal. The T-1 class's evaporative heating surface totaled 5126 square feet, plus 1214 square feet of superheating surface.

Four of these outstanding engines (2100-2102, 2124) were rescued from the scrap yard and remain today. No. 2101 (rebuilt from Consolidation No. 2021) was restored to operating condition for the American Freedom Train of 1975-76, and afterward pulled the Chessie Steam Special to commemorate the 150th anniversary of Baltimore & Ohio, and continued to head the "Special" till 1979. For this service it was painted in Chessie System colors, as shown in this photo of unknown origin provided by Tom Rock of T.D.R. Productions.