The Achilles heel of many major infrastructure programs is dealing with uncertainty. Destabilizing events, very often politically or financially motivated, aggravate schedule and cost overruns that are so common in complex programs. It is widely recognized that attempting to address all foreseeable risks using conventional risk management analysis does not scale to major programs. Any attempt to fully capture all stakeholder requirements upfront are likely to produce disappointing results, as major rail programs are faced with high levels of uncertainty that undermine the value of such analysis.
A better approach is to invest in designing a development model that is optimized for managing programs through uncertainty.