On Board the Queen Mary

THE BRIDGE

Queen Mary's Bridge: The ship's command center. The designers left nothing to chance; every major piece of equipment here is duplicated. The large cylindrical brass object in the back is the compass. The quadrants on stands with levers are engine-order telegraphs, which are used to transmit orders to the throttlemen in the engine rooms, who control how fast the ship goes.

THE ENGINE ROOM

One of four Main Engine Gage Boards in the engine rooms. The large horizontal wheels are the ahead and astern throttles, which control how fast and in which direction the ship goes by controlling the flow of steam to the turbines, aka main engines. Note the quadrant used to answer speed orders ('bells') from the bridge. It's too noisy to hear much of anything clearly in the engine room, so the all-important bells are transmitted visually. A bell rings when the speed pointer is moved from the bridge (hence the name), and the throttleman moves his pointer to indicate that he is answering the bell.

THE MAIN ENGINES

This is part of one of the four Main Reduction Gears that transmit power from the steam turbines to the shafts that the propellers are attached to. One of the turbine engines is partly visible in the upper right of the photo. The reduction gears act much like a car's transmission, except they have only one "speed". The turbines have extra sets of blades for reverse operation.