Side view of Titanic's engines

Side view of  both of Titanic's reciprocating steam engines in Harland & Wolff's Engine Works, May 1911.

This photograph, taken in the Erecting Shop, shows Titanic’s two reciprocating steam engines standing in line.  Each engine was the size of a three storey house and could generate 30,000 horse power. 

When installed in the ship, they sat side by side, driving the port and starboard wing propellers.

Titanic’s  arrangement of propelling machinery was designed to achieve fuel efficiency. Exhaust steam from the reciprocating engines was further expanded through a low-pressure turbine, and this was used to drive the centre propeller.  This system gave increased power without an increase in coal consumption.