The first Great Northern Railway engine shed at London was built in 1850, three quarters of a mile north-west of where Kings Cross station is located today.
A temporary passenger terminus had been sited at Maiden Lane (now called York Way) from August 1850[1] and the locomotive depot was constructed nearby.
[1] As part of this agreement the GNR undertook to provide engine sheds at its own cost for the MR, with the Midland paying for its water use, plus six per cent interest for the rent of the premises.
The Roundhouse (also known as the Derby Shed)[2] opened in 1859 and grew to be a considerable size, with eventually twenty four roads circling the forty foot diameter turntable.
The front half was part of the original 1850 running shed whilst the rear was formed by the 1862 extension to the carriage and wagon shops.