Have contacted Darra Best re my project. Unfortunately he did not cover my area of topic but was very grateful he answered my email.  I have also had a reply from Charles Friel who has been more than helpful with statistics. Charles is a member of the Railway Preservation Society of Ireland and a great source of information.  He has recommended books and has sent me charts.  Many Thanks Charles for all  your help. Like everyone I now need to settle down and start sorting my research and writing up my project.