Amtrak has a promo triple points (promo code 4663) and double points (4662).

You get 2 points for every $1 you spend on a ticket with a minimum of 100 points per ticket. You may make up to four stopovers free of charge on any itinerary.

So i booked:
Lancaster, Pa-->Mt. Joy
Mt.Joy-->Elizabethtown
Elizabethtown-->Middletown
Middletown-->Harrisburg

With discount code code H570 the reservation is 25% off and comes to $4.50. Each ticket yields 400 points, plus I got a 50 point elite bonus. So the whole itinerary comes to 1,800 points. I bought 24 round trips and got the conductor to lift all the tickets on the first train. Thus I will get a total of 86,400 points. Up to 50,000 a year can be converted into continental one pass airlines miles. Plus after one has 100 tickets lifted they reach select plus status which gives them a clubAcela membership which is also valid in Continental Prez Clubs. Along with a few free companion coupons and upgrades, for use on Amtrak.

This works for any Amtrak travel you just might have a hard time finding a cheaper route. If you sign up for Amtrak Guest Rewards to take advantage of this offer please pm me so I can refer you.

~Ian