The Intercity-Express (written as InterCityExpress in Austria, Denmark, Switzerland and, formerly, in Germany) or ICE (German pronunciation: [iːtseːˈʔeː]) is a system of high-speed trains predominantly running in Germany and its surrounding countries. It is the highest service category offered by DB Fernverkehr and is the flagship of Deutsche Bahn. The brand name “ICE” is among the best-known in Germany, with a brand awareness close to 100%, according to DB. There are currently 259 trainsets in five different versions of the ICE vehicles in use, named ICE 1 (deployed in 1991), ICE 2 (1996), ICE T (1999), ICE 3 (1999) and ICE TD (2001–2003, back in service 2007). The ICE 3, including its variant models, is made by a consortium led by Bombardier and Siemens.
Apart from domestic use, the trains can also be seen in countries neighbouring Germany. There are, for example, ICE 1 lines to Basel and Zurich. ICE 3 trains also run to Liège and Brussels and at lower speeds to Amsterdam. On 10 June 2007, a new line between Paris and Frankfurt/Stuttgart was opened, jointly operated by ICE and TGV trains. ICE trains to London via the Channel Tunnel are planned for 2018. While ICE 3M trains operate the Paris-Frankfurt service (with the exception of trains 9553/9552, which operate with TGV Duplex equipment and are cross-crewed with both SNCF and DB staff), SNCF’s TGV runs from Paris to Munich (via Stuttgart), with mixed crews on both trains. German and Austrian ICE T trains run to Vienna. On 9 December 2007, the ICE TD was introduced on the service from Berlin via Hamburg to the Danish cities of Aarhus and Copenhagen.
The Spanish railway operator RENFE also employs trains based on the ICE 3 (Siemens Velaro). Wider versions were ordered by China for the Beijing–Tianjin Intercity Railway link (CRH 3) and by Russia for the Moscow – Saint Petersburg and Moscow – Nizhny Novgorod routes (Velaro RUS).[
A derailment is said to take place when a vehicle such as a train runs off its rails. This does not necessarily mean that it leaves its track. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway system, and they are potentially seriously hazardous to human health and safety. Usually, the derailment of a train can be caused by a collision with another object, the mechanical failure of tracks, such as broken rails, or the mechanical failure of the wheels.
A traditional track structure consists of two rails, fixed a designated distance apart (known as the track gauge), and supported on transverse sleepers (ties). Some advanced track structures support the rails on a concrete or asphalt slab. The running surface of the rails is required to be practically continuous and of the proper geometrical layout.
In the event of a broken or cracked rail, the rail running surface may be disrupted if a piece has fallen out, or become lodged in an incorrect location, or if a large gap between the remaining rail sections arises. 170 broken (not cracked) rails were reported on Network Rail in the UK in 2008, down from a peak of 988 in 1998/1999.
In jointed track, rails are usually connected with bolted fishplates (joint bars). The web of the rail experiences large shear forces and these are enhanced around the bolt hole. Where track maintenance is poor, metallurgical fatigue can result in the propagation of star cracking from the bolthole. In extreme situations this can lead to a triangular piece of rail at the joint becoming detached.
Metallurgical changes take place due to the phenomenon of gauge corner cracking (in which fatigue microcracking propagates faster than ordinary wear), and also due to the effects of hydrogen inclusion during the manufacturing process, leading to crack propagation under fatigue loading.
Local embrittlement of the parent metal may take place due to wheel spin (traction units rotating driving wheels without movement along the track).
Rail welds (where rail sections are joined by welding) may fail due to poor workmanship; this may be triggered by extremely cold weather or improper stressing of continuously welded rails, such that high tensile forces are generated in the rails.
The fishplates (joint bars) in jointed track may fail, allowing the rails to pull apart in extremely cold weather; this is usually associated with uncorrected rail creep.
Derailment may take place due to excessive gauge widening (sometimes known as road spread), in which the sleepers or other fastenings fail to maintain the proper gauge. In lightly engineered track where rails are spiked (dogged) to timber sleepers, spike hold failure may result in rotation outwards of a rail, usually under the aggravating action of crabbing of bogies (trucks) on curves.
The mechanism of gauge widening is usually gradual and relatively slow, but if it is undetected, the final failure often takes place under the effect of some additional factor, such as excess speed, poorly maintained running gear on a vehicle, misalignment of rails, and extreme traction effects (such as high propelling forces). The crabbing effect referred to above is more marked in dry conditions, when the coefficient of friction at the wheel to rail interface is high.