All three types have four principal parts: a cigar-shaped bag, or balloon, that is filled with a lighter-than-air gas; a car or gondola that is slung beneath the balloon and holds the crew and passengers; engines that drive propellers; and horizontal and vertical rudders to steer the craft.
The last steam engine built for the railroad, No. 844 went into service in 1944 as a passenger engine and was pulled from service in 1959 when the industry's conversion to diesel engines was at full throttle.
When the 60 tonnes of the William Adams Express Passenger Engine No 563 chuff on to the theatre stage in a belch of smoke, a shimmering vision of chrome, steel, slicks of engine oil, green paint and polished brass, grown men can be seen weeping.
Steam-locomotive driving wheels were of various sizes, usually larger for the faster passenger engines.
The average was about a 1,829 2,032-mm (72–80-inch) diameter for passenger engines and 1,829 2,032-mm (54–66 inches) for freight or mixed-traffic types.
To maintain the high power rating required for express passenger engines, Maunsell opted for a three-cylinder design.
The S15s were also very capable passenger engines, being able to deputise in situations where there was a shortage of passenger locomotives during peak holiday periods.
After 9908 all Burlington passenger engines would be standard production locomotives, except for the cosmetic stainless steel bodywork of the E5s.
They proved slower than passenger engines, and their size, plus the added cars, increased the length of trains, complicating the unloading of passengers because they were too big for station platforms.
Under LSWR and Southern Railway ownership they had been successful suburban passenger engines, although with the increased availability of newer, standard designs, many of the class were diagrammed to take on a new role as reliable branch line engines, especially in Southern England.
