From the Amtrak web site:

“Amtrak is pleased to offer the Campus Visit Discount. This discount allows high school juniors and seniors visiting a college campus to take one parent or guardian along as a free companion.

“Amtrak is making this great discount offer in conjunction with our partner, Collegia. Just click on the ‘Apply Now’ link at the right to go to Collegia’s Campus Visit page. There, complete a brief form and you’ll be given an Amtrak Promotion Code. Then, return to to continue booking.”

Here’s the link to get the discount: