Does a Deltic Look Different?
When studied a Deltic has a beautiful symmetry to its design. Having two engines the exterior number 1 and 2 ends are hard to differentiate (1 end has an access plate to the exhausters while 2 end has a waste pipe from the urinal). Unlike many other classic English Electric designs the cab had two tear shaped front windows contributing to the impression of power that the class exude. Quite apart from the external design of the Class 55 locomotive, a Deltic exhaust is similarly unique. When setting off the Deltic engines can expel two large plumes of exhaust. The two stroke engine design carries over a quantity of oil into the exhaust collector drum. This gets hot, leading to a pale blue exhaust trail in many cases. After standing idling for some time, a Deltic can produce a cloud of smoke that many steam locomotives would find hard to match. Notwithstanding an engine that is running efficiently will soon loose this trait and the exhaust will clear.
