The first 2-10-10-2s were constructed in 1911 by the Atchison, Topeka and Santa Fe Railroad. They were built out of existing 2-10-2s with new front engines and tenders from Baldwin. The boilers could not sustain pressure and after ten years, the 10 locomotives were remanufactured into 20 2-10-2s.

In 1918 ALCO designed and built ten 2-10-10-2s for the Virginian Railway. They were so large that they had to be shipped in several pieces. The cab and low pressure cylinders were removed and reassembled on-site. The 48 inch low pressure cylinders were the largest ever used on a US locomotive. In fact, the cylinders had to be angled slightly upwards to provide adequate clearance. Because of Virginian turntable limitations, the tenders on these locomotives were abnormally small.

These locomotives could be operated in either single or double expansion mode. Surprisingly, the immense boilers were large enough to sustain steam pressure at about eight miles per hour. They remained in service for 34 years until 1952.