When A Passenger Train Burns, How Big Is The Fire?

Fire safety design of rail vehicles and infrastructure such as tunnels requires development of design fires for scenarios of full carriage involvement, or especially in the case of tunnels, the possible involvement of multiple carriages. Despite the apparent importance of having an accurate estimate of the size of fires likely to occur in trains, there do not appear to be any consistently sound methods of determining likely fire sizes. In this paper, the authors review a number of approaches that have been used over the years, both experimental and computer modelling. Whilst mathematical modelling will play an increasingly important part in the design of both trains and tunnels, the lack of experimental data on post-flashover fires in trains against which models can be calibrated is a matter of concern. Computer modelling needs reliable data, which can only be obtained experimentally.