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.

In order to estimate the reduction of seat-specific energy consumption, conventional (2950 mm) and wide-body (3400 mm) versions of an otherwise identical train (e.g. equal length etc) are compared. These widths correspond to the conventional ICE 3 and to a wide-body ICE 3 based on a design study.

Aerodynamic effect of wider car body

The cross-section of the train is increased by ~15%. Since air resistance grows with cross-sectional area in a less than proportional way, it is safe to assume that air resistance grows in the order of 10% or less.

Mass effect of wider car body

The design study for a wide-body version ICE 3 yielded a mass increment of about 10% in comparison to conventional ICE 3 design.

Comfort functions

No data are available on the effect on the energy consumption of comfort functions in a wide-body train. For obvious reasons (less wall surface per seat, less interior space to be heated per seat etc), it is increased by less than the relative increase in seating capacity. 10% will be a safe upper limit here as well.

Energy consumption of the entire train

Since all components of energy consumption of a passenger train (mass, air drag and comfort energy) are increased by about 10% (or less), the energy consumption will also increase by 10% or less.

Seat-specific energy demand

Since seating capacity is increased by about 25%, the 110% energy consumption have to be divided by 1,25 to get the seat-specific energy demand relative to a conventional car design. The result is a reduction of seat-specific energy consumption by 12%.

Assuming that a maximum of half of the regional lines and some of the main lines could be operated with wide-body stock in long term, the applicability in most fleets will not exceed 25%, but could reach values of up to 40% in some fleets. Accordingly, this gives a maximum system-wide effect of 2 - 5 %.

According to a study by European Transport Consult, costs are squarely in favour of wide-body stock as opposed to double-decked stock.

The specific initial investment per seat is low compared to both normal and double-decked stock as can be seen by the following examples.

German DB has compared several train concepts for the ICE 4. Table 1 gives the relevant initial invest figures (Reemtsema, Kurz 1997).

Table 1: Initial investment figures for different versions of ICE 4

	ICE 4	ICE 4 wide-body	ICE 4 2-decked
Investment	19.2 million EURO (100%)	22.0 million EURO (115%)	25.9 million EURO (135%)
Seats	419 (100%)	513 (122%)	506 (121%)
Specific investment per seat	45.900 EURO (100%)	42.900 EURO (93%)	51.100 EURO (111%)

Source: Reemtsema, Kurz 1997

A Swedish study (Andersson et al. 2001) on wide-body stock yielded the initial investment figures shown in the following table.

Table 2: Initial investment figures for wide-body trains

	Normal train	Wide-body train
Investment	100%	107%
Seats	100%	121%
Specific investment       per seat	100%	88%

Taking the average values from both studies, we get:

• Train fix costs typically increase by around 10% compared to normal trains.
• Specific fix costs per seat are reduced by around 10% compared to normal trains.

Maintenance costs: an increase of 4% for entire train and a decrease of 14% per seat according to a Swedish study.

Energy costs: per seat: 10-15% reduction

Highly dependant on required infrastructure changes.

Life-cycle costs (LCC) can be cut by up to 12 % per seat.

German DB AG estimates that the cost savings due to the operation of wide-body trains on the ICE network are so high that, even if the full costs of removing bottlenecks are charged to the programme, there will be cost savings in the mid term of 50 - 70 million Euro per year.