 With the land surfaces still sinking, the Commissioners looked at ways to improve the discharge of the engines in 1919, but did not take any immediate action.Instead, they considered the replacement of the steam engines by oil engines, and in 1924 asked Blackstone and Company Limited to supply two oil engines, each with a Gwynne rotary pump, capable of pumping 150 tons per minute.The engines were to be erected alongside the existing engines, which could then still be used as a backup in an emergency.