A lightweight carbody for high-speed trains


Sources of funding

KTH, Vinnova, Scania, Volvo, Saab, Bombardier, A2Zound, VTI, Trafikverket.
This is a project within the Vinnova Centre for ECO² Vehicle Design.


A rail vehicle's body structure is heavy in comparison to road vehicles. Weight per seat is significantly higher than in buses, for example. In addition, the price per kilogram is high. Reasons are partly short series and individual design for each customer. Conservative load assumptions in railway standards are other contributors.

In high-speed trains, the energy saving potential by reduced mass is due to high mileages – up to 500 000 km per year. Furthermore, for speeds above 250 km/h, a maximum axle load of 17 tons is permitted according to European legislation.


The goal of this PhD project is to reduce the weight of a high-speed rail vehicle load carrying structure by 30 % and reduce costs by 10 %, without reducing performance or compromising safety. This should be achieved by utilizing modern sandwich and composite technology.

Other positive effects of a lightweight, sandwich paneled, carbody are: thinner walls, reduced wear on wheels and track, reduced external noise, increased efficiency of electrical brakes, reduced manufacturing complexity, increased loading capacity, etc.

Research Direction

Lightweight structure

In the first phase of the project, focus is put on deriving a completely self-supporting sandwich structure for the load carrying structure of the carbody. This is in contrast to existing sandwich panelled carbodies, where steel frames are used to enhance stiffness of the structure.

Studies and optimisations on the structure provide generic guidelines on how sandwich panels should be designed to fulfil stiffness and strength requirements for each part of the vehicle cross-section. Modal analysis is used to study the dynamics of the carbody.

Simulation results

Weight savings and wall thickness vary significantly between sandwich alternatives, why a number of different material combinations are studied.

Once a completely self-supporting sandwich carbody is verified, the multi-functionality aspect of sandwich panels, e.g. acoustic and thermal insulation, can be integrated in the derived requirements, further reducing the weight and manufacturing complexity of the carbody.


  • Wennberg D, Wennhage P and Stichel S: Orthotropic models of corrugated sheets in Finite Element analysis. ISRN Mechanical Engineering, Volume 2011, Article ID 979532, 2011.
  • Wennberg D: Light-weighting methodology in rail vehicle design through introduction of load carrying sandwich panels. Licentiate Thesis, TRITA AVE 2011:36, ISBN 978-91-7501-002-1, Stockholm, Sweden, 2011.
  • Wennberg D, Stichel S and Wennhage P: Selection of sandwich panels for the load carrying structure of high-speed rail vehicles. 16th International Conference on Composite Structures (ICCS16), Porto, Portugal, 28-30 June, 2011.
  • Wennberg D, Stichel S and Wennhage P: Cutting the weight of high speed trains. Railway Gazette International, pp. 30-32, January 2011.
  • Wennberg D, Stichel S and Wennhage P: Modeling corrugated sheet with orthotropic properties and the  effect of stiffened panels on a rail vehicle's natural frequencies and modes. 16th Nordic Seminar on Railway Technology, Nynäshamn, Sweden, 14-15 September, 2010. 
  • Wennberg D: A light weight car body for high-speed trains – literature study. TRITA AVE 2010:16, ISBN 978-91-7415-591-4, KTH, Stockholm, Sweden, 2010.