Summer's here, and the trains are rolling. A new season means a new round of Amtrak discount codes, those luscious little numbers that knock up to 90% off of regular fares when punched into Amtrak's website.

Our first stop when booking a train ticket should always be Amtrak's weekly specials (, where they sell tickets on specific routes from a few days to a month in advance at up to 90% off. The weekly specials are best for tickets into or through America's heartland; for instance, we found a ticket from Chicago to St. Louis for $17.70, an excellent discount over the usual rates of $38-59 each way.

If you can't find your route on the weekly sale page (and remember, it changes every week), don't despair. Discount codes cover many of Amtrak's most popular routes. Sometimes they're also combinable with senior, children's, or AAA discounts. So pile on the discounts to get the absolute lowest fares.

To use a discount code, start booking a ticket on On the page with the list of trains, marked "2-Select Train" -- there's a promotion code field near the bottom. Enter the code before you click the "View Fare" button. If one code doesn't work, try another.

For single travelers in the Northeast, V626 is the best code out there right now. It gives you 20% off all Regional (non-Metroliner) trains anywhere between Newport News, VA and Portland, ME, in Pennsylvania as far west as Harrisburg, and in New York as far north as Albany. It's good for trains until Sept. 30, and it has no apparent blackout dates.

Couples traveling the Northeast can save even more with V737, which gives them 50% off the second person's fare. This code will work through Dec. 15, though the July 4, Labor Day and Thanksgiving weekends are blacked out; you also have to buy your ticket three days before traveling. V547 and V646 are very similar codes.

Groups of 3-6 in the Northeast can save even more with H545. That takes a stunning 90% off the third through sixth passengers' fares -- yes, ninety percent. This amazing code works on trains through December 15, although the July 4, Labor Day, and Thanksgiving weekends are blacked out; you must buy your tickets three days in advance, and buy them by Sept. 30.

For travel further down the East Coast, V616 gets you a 20% discount on the Piedmont, Carolinian or Silver Star trains. The Piedmont runs between Raleigh and Charlotte, NC; the Carolinian goes from New York to Charlotte via Raleigh, and the Silver Star runs from New York all the way to Miami via Raleigh and Columbia, SC. This discount is good for travel through December 3, with the July 4, Labor Day and Thanksgiving weekends blacked out.

Up in the Northwest, use code H515 to save 25% off ticket prices on Cascades trains, which run from Eugene, OR to Vancouver, BC. That code will work on trains through Nov. 15, except over the July 4 and Labor Day weekends.

In the Midwest, Amtrak offers two limited discounts. Trips within or between Illinois and Missouri are 20% cheaper if you use V242 -- but only from June 7-9 and June 14-16. On the short Hiawatha line between Chicago and Milwaukee, two children up to age 15 can ride free with each adult on Fridays, Saturdays and Sundays if you use the code H516 for booking trains through August 31.

Speaking of kids, if you're taking your teen for a college visit this year, check out If you fill out the form on that page, you'll get a special promotional code that will give you buy one, get one free tickets anywhere in the country for high school juniors or seniors traveling with a parent or guardian to visit a college. Certain holiday weekends are blacked out, as are trains between Boston and Washington leaving on Fridays and Sundays from 9am until 7pm, but it's still a great deal.

There's another odd kid-related discount out there. Apparently, if you buy a specially-marked copy of the Ice Cube family comedy Are We There Yet? on DVD, you get a super-secret Amtrak code that gives you 20% off most long-distance trains, between September 6 and December 15, with Thanksgiving blacked out. As DVDs of the film are going for about $10 on eBay right now, the investment might be worth it. The code doesn't help with trains going up or down the East Coast north of South Carolina, but it does cover trains from the East Coast to the Midwest.