The last and heaviest Mikados built for the Frisco were the 20 locomotives of the class T-74, numbered 4200 to 4219. Like most of their predecessors, they had drivers of 63 inches and cylinders of 27 by 32 inches. It's not completely clear if the boiler pressure was 210 or 235 psi. At 235 psi, they delivered a starting tractive effort of 73,965 pounds and a trailing truck booster added another 9,600 pounds. They had a mechanical stoker, a coffin feed water heater, two thermic syphons and arch tubes. They were retired between 1953 and 1956. 