Broads Spur was a siding just east of Chama. We did a runby here in 1993 on our photo special. They did a runby here during the recent 40th Anniversary stuff if I saw the video correctly.
I don't know my mileposts(yes thats right, I am not a rivet counter)
on the line except the mp 289, and 305 shots, so based on that the one Dave mentions is probably close to right.
As a point of reference the location is the open area about 2/3 of the way between the Chama crossing and where the highway comes close to the Railroad before the narrows. Its on the straight east of Chama!
Hope that helps.
Greg Scholl