The Tower Bridge engine
Built in 1942 by Vickers Armstrong Ltd at their Elswick works in Newcastle upon Tyne this 150 HP horizontal cross compound hydraulic pumping engine No SE1190SE with 18" (High Pressure) and 30" (Low Pressure) by 27" stroke cylinders was supplied to give additional protection in the event of the either of the two original 1898 pumping engines being damaged during the hostilities.
Driving two pumps by the piston tail rods, 750 PSI was developed which pumped up hydraulic accumulators, this stored hydraulic pressure was released to up to eight hydraulic engines when the two 1000 ton road bascule sections were required to be raised for shipping.
With a hand set Meyer expansion slide valve on the HP and a simple slide valve on the LP, a Pickering Throttle Governor controls the working speed of this engines 9 foot diameter 9 ton flywheel at 30 rpm.
Made redundant in the bridge modernisation of 1974 the engine was donated to Forncett by the Corporation of the City of London