Driving down to Austin lately has become a real trip. I-35 is usually packed for most of the 185 miles, and what used to take three or four hours now can take five or six. Flying down can take almost as long, when you figure in airline security delays, more flight delays, and the time it takes getting into and out of crowded airports. But what if it took 45 minutes to travel from the Metroplex to Austin by train or an hour to make a trip to Houston? Advocates of high-speed rail lines are floating these ideas once again...