New York Central classes H-10a and H-10b

Of a total of 1,350 Mikados owned by the New York Central, the H-10 was the last and by far most modern. It started in 1922 when William E. Woodard of Lima was tasked to design a modern freight locomotive that was much more efficient than existing types. This one went to NYC's subsidiary Michigan Central and was numbered 8000.

It was based on the H-7e, but the most significant change was the superheater area that had nearly been doubled in comparison to other Mikados. To achieve this, the boiler only had flues with superheater elements inside them and no tubes at all. Additionally, it had a feedwater heater, improved draughting and streamlined steam passages. To improve the response to throttle inputs, it also got a front end throttle. Like the majority of NYC Mikados, it also had a trailing truck booster. 

In the result, the H-10 was 26 percent more efficient than the H-7. During its test runs, the 8000 managed to haul a train of 10,039 tons over nearly 50 miles. Due to its great success, it formed the base of 301 more H-10a and H-10b locomotives built by Lima and ALCO for the NYC and its subsidiaries. Many consider them the prototypes of Lima's superpower design and they didn't need many modifications during their service life. They were scrapped between 1950 and 1954.