Technologies - Streamlining of head and tail

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Streamlining of head and tail

evaluated

In a long passenger train only about 10% of the aerodynamic drag are due to the front and tail ends. Nevertheless, there is some potential for further improvements on the aerodynamics of the front nose of high-speed trains.

Technology field: Aerodynamics and friction



General information

	Description
		In a long passenger train only about 10% of the aerodynamic drag are due to the front and tail ends. Their importance for aerodynamic resistance is much less than commonly believed. They do however have more relevance in short trains, where they gain relative importance compared components of air drag being proportional to length, such as sides, roofs and bogies. There are efforts at DB AG and other railways to optimise nose shape of high speed trains. However, these efforts usually aim at side wind effects rather than aerodynamic drag. Nevertheless studies indicate that there is still some potential for air drag reduction.

General criteria

	Status of development: research & experiments
		There is research going on in several railways. At DB AG, a number of innovative nose shapes have been studied in wind channel.

	Time horizon for broad application: not applicable
		(no details available)

	Expected technological development: not applicable
		(no details available)

	Motivation:
		Running stability Running comfort Noise reduction

	Benefits (other than environmental): medium
		Reduction of side wind effects and control lift forces and yawing moment. This improves running stability and comfort. Avoidance of sonic booms in tunnels. Reduction of pressure wave of train front when passing stations.

	Barriers: low
		(no details available)

	Success factors:
		(no details available)

	Applicability for railway segments: medium
	Type of traction: electric - DC, electric - AC, diesel
	Type of transportation: passenger - main lines, passenger - high speed
		(no details available)

	Grade of diffusion into railway markets:
	Diffusion into relevant segment of fleet: not applicable
	Share of newly purchased stock: not applicable
		(no details available)

	Market potential (railways): not applicable
		(no details available)

	Example:
		R&D at DB AG At DB AG several nose shapes have been submitted to wind channel tests (For more information cf. Heine, Matschke 2001).

Environmental criteria

	Impacts on energy efficiency:
	Energy efficiency potential for single vehicle: < 2%
	Energy efficiency potential throughout fleet: < 1%
		The research at DB AG on optimisation of nose shape revealed a potential for reduction of Cx and thus airdrag of about 5% for the front vehicle of an ICE 2. Given that the front vehicle only accounts for about 10 20 % (depending on train length) of the total air resistance, the overall potential for reducing aerodynamic resistance is only about 0,5 1 % and the effect on total traction energy demand even smaller (0,3 0,6 %).

	Other environmental impacts: neutral
		(no details available)

Economic criteria

	Vehicle - fix costs: none
		In newly designed vehicles an optimised nose shape as such would not increase costs.

	Vehicle - running costs: minor reduction
		(no details available)

	Infrastructure - fix costs: none
		(no details available)

	Infrastructure - running costs: unchanged
		(no details available)

	Scale effects: not applicable
		(no details available)

	Amortisation: not applicable
		(no details available)

Application outside railway sector (this technology is railway specific)

Overall rating

	Overall potential: not promising
	Time horizon: (no data)
		An aerodynamic optimisation of train head and tail may be beneficial for running stability and noise. However, from an energetic point of view, the reduction potential is very small.