References...

Along with skimming several thesis projects from the past, I checked out 2 books to help formulate and narrow down by proposal.

Urban Transportation Systems: Choices for Communities

This was a great starting point for general transportation research.  While slightly dated (published in 2003) this book gives a break down of all modern forms of transportation; their history, their implementation, their successes and failures.  

Contemporary Architecture: Transportation

This book is a display of architecturally pleasing and functional transportation buildings throughout the world.  I choose to look at this to get inspiration on what can be done and what has been done.  It promotes that through the use of good architecture, these transportation stations and their systems can benefit.  Well designed, well laid out, efficient, etc.