Amtrak, Thompson's Point Rd., www.amtrak.com. The Downeaster operates between Portland and Boston North Station. Trains run both ways five times each day. The train ride is about 2.5 hours, and a round trip ticket costs only $44. Kids 15 and under ride for $11. If you want to make a day trip to Boston, you can leave at 8:00am and be back in Portland by 8:55pm, and still have from about 10:30am-6:00pm to sightsee in Boston.