When it was steam powered, water under high pressure was stored in these hydraulic accumulators. There were six of them.

Tower Bridge: Cost 1,184,000 pounds to build. 800ft long. Towers 213ft high. Central span is 200ft long.

Tower Bridge with its bascules in the up position. They can be raised to 83deg in 5 minutes. Each bascule weighs 1000 tons.