This paper summarizes the work to estimate the value of uncovered capacity when using Incremental Allocation, including how it was calculated. The estimation was performed as part of the commercial valuation of Incremental Allocation. This valuation was made within the PENG framework. The aim is to estimate the value of new traffic that can be served by the uncovered capacity. The calculations are based on the UIC406 standard, but instead of analysing the traffic executed on a typical day the planned train paths are analysed. More precisely, the input data is a snapshot from planning tool TrainPlan from 2011-04-08, including AdHoc train paths. The results show that a large portion of the available capacity is hidden from use by the current planning methods and scheduling rules.