AbstractAlthough network modelling techniques have been available for a number of years now, in the transport sector they have largely been confined to the planning function, and the analysis of schemes with long lead-times. However, recent analysis by London Underground Ltd has used a Network Model to estimate changes in revenue and passenger time resulting from the possible failure of key parts of their infrastructure. Future engineering strategy will attempt to repair first those sites where the disbenefits of failure are greatest. This paper also introduces a number of algorithmic developments (in terms of a group of choice models) which have underpinned this analysis and have significantly improved the accuracy of the modelling tools available.