Having established a set of requirements, concept solutions and an indication of train service it is time to check how these work together. This means using specialist resource to get the ITSS modelled on existing infrastructure to ascertain pinch points that require interventions. Remember the Early Stage Specification Tool and consider timetable first as this is the easiest to change. Infrastructure should be the last option considered.

The output required from the modelling work is a report detailing:

This drives the solution by specifying the capability of the interventions necessary to create a concept solution to drive a system capability change.

Refer back to the hierarchy in the Early Stage Specification Tool and consider the following questions for effective development:

Even at this step the emerging information may mean that it is time to reconsider whether rail is still the appropriate mode when taking account of potential costs. As the scale of the challenge starts to be understood a high level view of whether a heavy rail option has a chance of passing a value for money test should be emerging. If this looks unlikely or there are other modal opportunities that may offer a better strategic fit then it may be time to revisit the multi modal assessment tool or to implement your exit strategy.