There's quite a few railroad grades on the NMLCo. that have not been mapped. I spent some time out there about 20 years ago and mapped what I could. Some of that ended up in the RGS Story Vol. 7 on the NMLCo. There's more to be done for anyone with the spare time. Artifacts were interesting ranging from a C&S queenpost at a wreck site to interesting tie spiking practices. Back in the mid-90's a group of us from Chama hiked a section that included both well graded and drained ROW and then very sketchy track surveying. It almost looked like you could see where the company changed surveyors as the change in quality was that abrupt.
I may spend more time this summer doing a little more exploring up on the mesa...