Double decker

A double decker is a bus, train or tram that has two levels for passengers, one above the other. The Boeing 747 has also two decks.

Bus

Double-decker buses are almost twice as tall as other buses. Most famous is the Routemaster used in London.

Train

Because of the standard height of tunnels and overhead power wires, many double-decker trains set the bottom deck lower down between the bogies. At the entrance platforms of the train there is just a single deck, above the bogies. From there one can go upstairs or downstairs. For example, for the DD-IRM (see below) it is one step up from the station platform to the entrance platform, and from there 7 steps up or 4 steps down.

Other double-decker trains, however, such as those using rolling stock made by Colorado Railcar Manufacturing[?], house the entrance on the lower deck rather than an intermediate level. The Amtrak Superliners[?] are also double-decker trains of this variety, housing the entrance about a step or so up from the (generally low) platform of the railroad stations, and allowing passage from car to car through the upper corridors of the train. (Colorado Railcar Manufacturing, responsible for constructing the Princess cars on the Alaska Railroad[?], can be located online at [1] (http://www.coloradorailcar.com/).

In some countries such as the United Kingdom the railway system cannot accommodate double decker trains because the loading gauge[?] is to small (i.e. bridges, tunnels, etc. are too low). An intermediate form of two-level seating arrangement has been tried in Britain, where the bottoms of the upper seats are above the heads of the people on the lower level, but the feet of the people above are not, see [2] (http://members.tripod.com/~dart75/bddscut.htm).

Double decker trains often have curved windows upstairs. In the evening and in tunnels children love this for the distorting mirror effect.

In the Netherlands there are two types of double decker trains, the DDM and the DD-IRM, also called Regiorunner, see Trains in the Netherlands.

Tram

There are double-decker trams in Hong Kong.

They are also in some places, aimed at tourists, e.g. in summer only, e.g in Blackpool and the Isle of Man.

See also: transport.

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The term double decker is also used for bridges with two road levels, for example the San Francisco-Oakland Bay Bridge.