It stayed moribund until about 1925, and was then activated to renovate trains running on what is now the Central line and, following on from this, it built new London Underground Standard Stock in 1927.
It also began a major tram-rebuilding programme for the Metropolitan Electric Tramways (MET).
It became a 'shell' company in 1929, was renamed The Union & Finance Construction Co. Ltd., then built some experimental tramcars for the MET in 1929 & 1930.
[1] These became the forerunners of a fleet of 100 double-deck tramcars for London United Tramways (LUT) and MET, well known as the Feltham Tram.
The Board was prohibited from directly manufacturing its own vehicles, leading to the demise of the UCC and the placing of all future orders with companies such as Metro-Cammell.