I wonder if it may be helpful for you to provide a little more information on the project. For example, how is it being funded and what skills does your current team not have that you need? How will it be distributed and retailed and on what platforms? What experience do the existing team have in delivering products in the gaming market?
Whilst I'm not a gaming expert it seems incredibly wide in scope with extensive mapping and modelling requirements. How are you intending to balance accuracy of detail with the wide reaching scope of a large number of railway lines, roads, ports etc? Will it devalue the game if you travel through say, Harwich, but it's modelled no differently to Calais or Birkenhead or Hull?
A more comprehensive plan with realistic ambitions on what the project will achieve at each stage will probably foster more interest from potential members of a project team.