The engine was purchased by a Quainton Railway Society member, arriving at Quainton in December 1972, where it joined identical sister loco 2105, which is still at Quainton.

This locomotive was built by Peckett in 1948 to their 'Special R4' design (differing from their 'Standard R4' in that it was built to a smaller loading gauge). It was not delivered until 1951, to Croydon 'B' power station.  It was joined here by its sister loco No. 2105, and Peckett 2103 (part of the same batch).

In the late 1960s, diesel locomotives took over at Croydon but No. 2104, along with No. 2105, was kept as a spare until 1972, when they were put up for sale. Purchased by a QRS member, it arrived at Quainton in December of that year. It operated at Quainton for a number of years before being withdrawn for boiler repairs.  No. 2104 moved to the Northampton & Lamport Railway in March 1989.