Does a Deltic sound different to any other diesel loco?
A Deltic sounds very different to any other locomotive. At idle, the phasing gears inside the engine can be heard as can the scavenger blower and the exhaust. The noise varies depending on where and how far you are standing in relation to the locomotive. The engine note is like a low, rumble of thunder. An 18 cylinder Napier Deltic rail traction engine idles at 700 rpm (faster than most other diesels at full bore) and can run up to 1500 rpm. As the engine revs increase the Deltic engine also changes character. The rattling and vibration in the phasing gear changes frequency, and the engine note becomes a higher-pitched, very smooth drone. For this reason the locomotives are sometimes nick-named Drones or Lancaster Bombers. After hearing a Deltic engine, be it in a Class 55 or a naval craft, it is very difficult to mistake them for anything else.
