I havent dug any railway sites but before you do you should be aware of
potential contamination problems and get appropriate contamination clearence
before excavating!
 
I am interested on information on the design of brick lined railway tunnels in
particular ones with an oval shaped arch. I am undertaking a heritage
assessment of one in NSW (actually the Fernliegh tunnel) and there is
virtually nothing on the subject although you would think otherwise.
 
Iain Stuart
University of Sydney
Iain [log in to unmask]