From the "Take it Easy, Take Amtrak: Amtrak & the National Park Service present Trails & Rails" brochure:
"To receive a 5% discount off the lowest available Amtrak fare present a valid National Park Pass and photo ID at time of ticketing. Offer valid on select trains only. This discount is valid for a family up to four. Offer not combinable with other offers, promotions, or discount."
No other details provided:
- No discount code number given.
- Excluded trains are not specified.
Best to just show Amtrak this brochure to an Amtrak agent since without a code it may be difficult to prove that this fare exists.