The last steam locomotives that the Florida East Coast purchased new were 23 copies of the USRA Heavy Mountain. They were delivered by ALCO-Schenectady in 1926 and were numbered 801 to 823. After the Mountains of the classes 301 and 401, they were significantly heavier. In direct comparison with the 401, they had a larger boiler and larger cylinders, but smaller drivers for greater pulling power. After three were lost by 1952 due to boiler explosion or accident, the remaining 20 were scrapped in 1954.