“It had been difficult to update the estimates with any degree of accuracy prior to tender as we only achieved completion of the design at tender stage,”it adds. Some of the main issues which were not considered in the original estimated cost include an alteration to a slip road and associated embankment, which will generate further earthworks. Sustainable urban drainage systems to be delivered as part of the project has also increased the cost. A sketch of how the station could look A sketch of how the station could look The size of the car park will need to be increased to provide electric vehicle charging points, and the cost of ticket machines was also not considered in the original estimate.