Principle

Conventional stock for long-distance and regional service has an exterior coach width of around 2900 mm. In an effort to increase floorspace per coach, trains have been developed that are considerably wider. For our purposes, we define a wide-body train as one allowing a 2 3-seating arrangement in 2nd class and a 2 2- arrangement in 1st class. In main line service this usually requires a minimum width of about 3300 mm. The gain in floorspace is in the order of 10 to 20%. Considerations of the DB AG for a wide-coach version of the ICE 4 indicate an increase in seating capacity of 22% compared to the "normal" version (as opposed to slightly less for a double-decked version).

Examples

The following table lists some wide-body trains.

Denmark	S-bane trains	3.60 m
Denmark	IC/3	3.10 m
Norway	Sleeper coach	3.24 m
Sweden	Crusaris Regina	3.45 m
Netherlands	SM90 (wide body)	3.20 m
Japan	Shinkansen	3.38 - 3.40 m

Source: Andersson et al. 2001

• The Lirex developed by Alstom shows that at least for regional service 5-seat arrangements can be integrated in coaches which are only 3042 mm wide.
• An example of extremely wide coaches (3600 mm) is the Copenhagen suburban train set produced by a Siemens/LHB consortium. Many German suburban trains have a width of about 3200 mm.
• In Japan there are also some 3.40 meter wide Shinkansen trains which are double-deckers. In some of their coaches there are 2 3 seats downstairs and 3 3 seats upstairs. Such a seat arrangement of course gives a significant reduction of comfort.

Infrastructural compatibility

As opposed to isolated solutions (e.g. suburban networks), mainline service sets more rigorous conditions to stock width, especially if interoperability is demanded. However some conceptional and technological measures could raise infrastructural compatibility of wide-body stock. Among them are reduced coach length (thus reducing the lateral swinging out in curves) and more high tech solutions such as a telematically controlled tilting away from infrastructural obstacles.