A spiral (sometimes called a spiral loop or just loop) is a technique employed by railways to ascend steep hills.
A railway spiral rises on a steady curve until it has completed a loop, passing over itself as it gains height, allowing the railway to gain vertical elevation in a relatively short horizontal distance. It is an alternative to a zig-zag, and avoids the need for the trains to stop and reverse direction while ascending. If the train is of sufficient length, it is often possible to view the train looping above itself.
A spiral loop should not be confused with the transition spiral or spiral easement used to provide a transition from a tangent into a horizontal circular curve. Spiral easement is used to avoid abrupt changes in the sideward acceleration experienced by a railway vehicle and the passengers in the vehicle approaching the horizontal circular curve and to prevent abrupt forces and discomfort. These curve layouts are also used in highway engineering.
Spirals are not generally needed on tramways (street running or reserved track) or light rail lines because trams traditionally have all wheels powered, giving the ability to climb much steeper direct gradients than railways. In addition, the space consumed by a spiral is usually not available in an urban environment.
Rail transport is a means of conveyance of passengers and goods, by way of wheeled vehicles running on rails.
It is also commonly referred to as train transport. In contrast to road transport, where vehicles run on a prepared flat surface, rail vehicles are also directionally guided by the tracks on which they run. Track usually consists of steel rails, installed on ties (sleepers) and ballast, on which the rolling stock, usually fitted with metal wheels, moves. Other variations are also possible, such as slab track where the rails are fastened to a concrete foundation resting on a prepared subsurface.
Rolling stock in railway transport systems generally has lower frictional resistance when compared with highway vehicles and the passenger and freight cars (carriages and wagons) can be coupled into longer trains. The operation is carried out by a railway company, providing transport between train stations or freight customer facilities. Power is provided by locomotives which either draw electric power from a railway electrification system or produce their own power, usually by diesel engines. Most tracks are accompanied by a signalling system. Railways are a safe land transport system when compared to other forms of transport. Railway transport is capable of high levels of passenger and cargo utilization and energy efficiency, but is often less flexible and more capital-intensive than highway transport is, when lower traffic levels are considered.
A railway is a means of transport.
Railway, Railways or The Railway may also refer to:
A spiral is a curve which emanates from a central point, getting progressively farther away as it revolves around the point.
Spiral may also refer to:
Spiral (French: Engrenages, pronounced: [ɑ̃ɡʁəˈnaʒ]) is a French television police and legal drama series set in Paris. The show follows the lives and work of Paris police officers and the lawyers and judges who work at the Palais de Justice. It was created by the TV production company Son et Lumière.
The first series of eight-episodes started on Canal+ in France on 13 December 2005. The series was shown in the UK on BBC Four during the summer of 2006. It was the channel's first French-language drama series, attracting a modest but loyal audience (around 200,000) and firm critical approval. On 13 September 2009, BBC Four started showing the second series – another eight-part series, partly funded by the BBC – was broadcast from 12 May 2008. The third series was shown from 2 April 2011, and the fourth series from 9 February 2013 – both consisting of twelve episodes.
Series 5 was filmed in 2013 and broadcast in France in late 2014, and in the UK on BBC Four from 10 January 2015. The sixth series has been ordered.
This is the list of all known Mini-Cons from the Transformers toy line and other series.