Actually, you can do quite a bit of the circle by car still. From Chama, you can head west to Dulce and then take the dirt road back through Gato and come out at Arboles. There the 'new' bridges that were built for the re-alignment are still in place as well as the truss through bridges in the back country. From there you can follow along as you head towards Ignacio. Now the roadbed does take a bend and come out on the other road that comes up south of Ignacio. From Ignacio to Durango, there is almost no bed left. Although it is possible to glance it in the distance on the occassional hillside. You can see where it comes down grade to Carbon Junction. You can trace most of the branch to Farmington....it peters out about Aztec.
From Durango west, it is hard to trace the bed. You can travel to Delores, where the station has been rebuilt..quite nicely too. From there you can pick up pieces of the bed as you head over to Lizard Head and come down the other side into Rico. From there there is quite a bit to be seen of the bridges and alignment. However the branch to Telluride...I have not been able to locate it.
From there to Ridgeway, I have seen quite a bit of old bed. Especially over the Dallas Divide. In Ridgeway, the old depot is now a home and I have not been able to locate the old shop area.
The branch to Ouray...it can be seen in bits and pieces.
Towards Montrose, again bits and pieces, but new housing is taking some of it away. From Montrose to Gunnison and over Marshall Pass, I have not been that way in years. I do know that in Salida several years ago, you could still see the spike marks in the ties from the third rail. I did come down from Salida to Alamosa and was able to pick up a lot of the bed on the way.
As a side note, it is still possible to see a lot of the old Chili Line to Santa Fe between Antonito and just north of Espanola. The old D&RGW station in Santa Fe still stands too.
All along the way there are still several water tanks and other structures.
Hope this adds to the conversation....
P.S. Dittos to relaying to Dulce and beyond!
