Why in the world does any member of Congress get ANY form of tax-payer funded transportation - with the possible exception of the SOTH, who of course is in the line of succession, so there are legitimate security concerns. DC has a robust public transportation system. They should ALL take advantage of it. If trains are good enough for the little people, they're good enough for them.
par for the course:
Lawmakers Keep the Change (from travel per-diems)
http://www.freerepublic.com/focus/f-news/2462301/posts
A few years ago, I met Senator Spencer Abraham at an event in Michigan. He showed up in a very basic late model Buick and drive himself. I was impressed.