The C&O class T-1 was an important step in Lima's “super power” concept. It was a class of 2-10-4 “Texas” freight locomotives based on the 2-8-4 “Berkshires”, but with an additional driving axle. The idea came when the C&O borrowed a Berkshire from the Erie and thought that they needed to increase its power and tractive effort. The result were 40 locomotives numbered 3000 to 3039, which were built by Lima in 1930 with the works numbers 7516 to 7555.

The boiler had a diameter of nine feet and a grate of 121.7 square feet. The combined heating surface of firebox, tubes and superheater was more than 9,600 square feet, what was the greatest number for any two-cylinder steam locomotive ever. Boiler pressure was initially 260 psi, but was increased to 265 psi in 1933. The cylinders with 29 inches of diameter and 34 inches of stroke worked on 69-inch drivers and generated 93,345 pounds of tractive effort. Cutoff was limited to 60 percent. A booster added 15,275 pounds, leading to a total tractive effort of 108,620 pounds. 

Most locomotives of the class were used between Russel, Kentucky and Toledo, Ohio, but some also operated in eastern Virginia. With a similar tractive effort compared to the class H-7 2-8-8-2, but more horsepower, they could haul the same trains with a higher speed. Typical coal trains had 160 cars and totalled 13,500 short tons. On the return journey with empty cars, they reached speeds of 50 mph. Their downside was that the long driving wheelbase made counterbalancing challenging, so that they tended to damage the tracks on grades when ascending them with full power.

Although already introduced in 1930, the T-1 was used in the same role until the switch to diesel. They were only surpassed in power by the H-8 “Allegheny” 2-6-6-6, but were still able to maintain their position. In 1942, the PRR took this design to create its class J-1, of which 125 were built at Altoona. Compared to the C&O locomotives, these had cast-steel frames with integral cylinders. In 1948, No. 3020 was lost due to a boiler explosion. The others were retired and scrapped in 1952 and 1953.