London, England, United Kingdom
Hydraulic Lock Gate Engine This machinery was installed in 1902, at the time the Greenland Lock was enlarged, to open and shut one of the lock gates by high pressure water power. It was heated by gas in winter to stop the water freezing. — Princes Court, Greenland Dock
Listen to the audio guide for Black plaque № 71887 Free on WIP — starts by itself when you arrive, even with the screen off