This is one of the class R4-S locomotives built by Peckett & Sons in 1948 for the Central Electricity Generating Board (CEGB) to work at Croydon Power Station B. The locomotives differed from the standard R4 class as they had to work in a restricted area where the coal wagons were tippled to unload. The loading gauge was reduced to 9 feet 10 inches compared with the 10 feet 8.5 inches of the standard locomotives so the cab roof was lower. All three locomotives have been preserved.
Planning for Croydon B started in 1939 but because of delays caused by the Second World War it did not open until 1950. Coal delivered to the site was shunted by the three Peckett locomotives (Works Nos 2103,2014 and 2105). These three steam locomotives were superseded by diesels in the 1960s. 2104 and 2105 were set aside as spares until 1972, when they were sold off.
2104 and 2105 were bought by a Quainton Railway Society member and moved to the Buckinghamshire Railway Centre in December 1972.
2104 operated at Quainton for a number of years before being withdrawn for boiler repairs.
In March 189 the locomotive was moved to the Northampton & Lamport Railway.
2104 is now based on the Northampton & Lamport Railway where it was in traffic until withdrawn from service in January 2017 for a ten year overhaul.
In early 2018 the locomotive was in store pending an assessment for overhaul.
It was still waiting on an overhaul in the summer of 2020.
In October 2021 it was reported that the locomotive had been put up for sale where it was still awaiting an overhaul.