69621 was built at Stratford in March 1924 as the last locomotive of the original batch of 22 locomotives of the N7 class. In fact it was the last locomotive of any class to be built at Stratford.
It entered service as GE 999E as one of the engines fitted with a condenser to work on the Metropolitan lines. The condensing apparatus was removed in May 1937
BR Motive power depot allocations.
| Date Arrived | Depot |
| Ist January 1948 | Stratford |
| November 1948 | Parkeston |
| September 1951 | Stratford |
| July 1952 | Colwick |
| February 1953 | Woodford Halse |
| June 1953 | Colwick |
| April 1954 | Stratford |
| May 1957 | Lowestoft |
| September 1959 | Stratford |
It was withdrawn from service in September 1962 and purchased by Dr. Fred Youell for preservation.
It moved to the East Anglian Railway Museum in 1973, but work was not started on restoring the N7 to steam until 1981. The locomotive returned to steam in 1989, and spent the next ten years visiting many preserved. At that time it gained the name A J Hill in honour of its designer.
In 1991 the N7 also visited Stratford (where 69621 was build and sometimes based) to mark the closure of the works.
69621 re-entered into service on the North Norfolk Railway where it is on long term loan from the East Anglia Railway Museum after its second general heavy overhaul in September 2005.
It spent some time on the Churnet Valley Railway in 2015 where it worked until April 2015 when the boiler certificate expired.
There are no plans to return the locomotive to steam again so it has been cosmetically restored in BR lined black for display at Platform 4 at the Chappel & Wakes Colne which is part of the East Anglia Railway Museum.
Despite a legacy of £115,00 being made available for the engine there are no plans to undertake any major work on 69621 within the next two to three years when the situation will be reviewed again.
In June 2020 the East Anglia Railway Museum confirmed that the locomotive was going to be overhauled and that it was planned to have it back in steam in 2024.
By August work started on the overhaul of the locomotive at the East Anglia Railway. It is anticipated that the boiler will be sent away for contract overhaul.
In July 2021 it was reported that the boiler had been delivered to Heritage Boiler Steam Services near Liverpool for contract overhaul at the end of the previous month. The plan remained to have the locomotive in steam in 2024.
| Home Base | Current Status | Owner |
| East Anglia Railway Museum | On static display | East Anglia Railway Museum |
Preserved British Steam Locomotives 