The Rock Island Rail Trail

The Choctaw Rocket was a luxury train that once travelled
between Memphis, Tennessee and Tucumcari, New Mexico.
 

Once upon a time, the Rock Island Railroad used to travel between Tucumcari and Amarillo. It shut down in the early 80’s, but the Right-of-Way (ROW) is still there.
If you look at Google Maps, in satellite mode, you can see where it parts from the existing Union Pacific tracks, just northeast of Tucumcari (northeast of the lake), not far from Route 54.
The right of way seems almost entirely intact from there to the tunnel under I-40, a distance of about 3 miles. The Tucumcari area could use some more hiking trails and the old ROW looks like just the spot.
There are several advantages to rail trails. For one, they combine history with outdoor recreation. Railroad lines are graded to be as flat as possible, meaning a large portion of the population can walk the trail with ease. They are already partially constructed. Trails, by law, can revert to railroad use, if need be. Rail trails have proved to be enormously popular throughout the country, not only providing recreation, but economic stimulus to local businesses.
For more information, check out the Rails-to-Trails Conservancy.

Highlights of the trail could include the Tucumcari Wildlife Management Area
and this tunnel.