I've been reading a lot by Tom Vanderbilt lately.  He not only wrote a book called "Traffic:  Why We Drive The Way We Do," but he's now a regular contributor to the online mag Slate.com (in my Favorites tab), writing on transportation issues. 

His most recent column addressed Amtrak's major regression since the early part of the 20th century.  His comparison of the travel times alone tells the story, "The trip from Chicago to Minneapolis via the Olympian Hiawatha in the 1950s took about four and a half hours; today, via Amtrak's Empire Builder, the journey is more than eight hours."  He continues, "Going from Brattleboro, Vt., to New York City on the Washingtonian took less than five hours in 1938; today, Amtrak's Vermonter (the only option) takes six hours--if it's on time, which it isn't, nearly 75 percent of the time. In fact, back in the 1930s, It was not uncommon for the Zephyr (which travels from Chicago to Denver) to hit speeds of more than 100 mph.  Meanwhile, today's "high-speed" service on Amtrak has an average speed of 87 mph and a rarely hit peak speed of 150 mph."

Amtrak's Glory Days: (A dining car from the 1950s)

Vanderbilt says Amtrak having to share its rails with freight trains is a major part of the problem -- most rail systems (crossings, speed zones, etc.) are built for trains going at around 87 mph, and to go any faster would require Amtrak to jump through all kinds of hoops.  There's also the issue of capacity -- much less rail out there (a result of the automobile and the American highway system taking over in the post-war period). 

Some experts speculate that with rising diesel fuel prices hurting the trucking industry, trains may become a priority again in this country.  Yet for passengers, will they be willing to trade air travel for train travel consistently -- sacrificing their time for a few dollars savings?  Or can Amtrak get up to speed again?