The Rail Passengers Association (RPA) is the public identity of the National Association of Railroad Passengers, Inc. (NARP), which is an IRS-designated 501(c)(3) non-profit, charitable organization: Fees paid for membership in the Rail Passengers Association (RPA) &/or National Association of Railroad Passengers (NARP) are tax deductible, with the exception of any Amtrak Guest Rewards Point received, which have a taxable value of 2.5 cents per point.
Your Amtrak Guest Rewards account number is optional but essential to earn bonus points for joining Rail Passengers. You may enroll in the program here: https://amtrakguestrewards.com/members/new.