Christian Science Monitor: Would the high-speed rail network proposed by President Obama boost the nation’s economy, cool the climate, and bring US transportation into the 21st century? Or is it a boondoggle waiting to happen? Kyle Spolski has few doubts. Preparing to board the gleaming steel Acela, the nation’s only high-speed train service, the business executive calculates his Boston-to-New York travel costs. Time: about 3-1/2 hours. Cost: $124. Taxi fare: $0. Airport hassle: none. “I used to …