You may find these links useful.
Highways Agency Documents:
Network Rail Standards:
Railway Group Standards http://www.rgsonline.co.uk/Railway_Group_Standards/Forms/Live_Documents.aspx
http://www.eurocodes.co.uk/ Eurocodes Expert, an Institution of Civil Engineers (ICE) and Institution of Structural Engineers initiative to help design engineers to understand and use the new European structural design codes.
California Department of Transportation: http://www.dot.ca.gov/hq/esc/techpubs/