I agree with your assessment that this is not particularly near Leadville. At first glance, it doesn't seem wrong for the area between Granite and Twin Lakes. However, I have spent a fair amount of time near Granite, and a few things lead me to conclude that your photo isn't that area:
1) The geology doesn't look quite right. The canyon around Granite is fairly wide and meandering. While there are rocky outcrops, such distinct bedding planes as evidenced in your photo are few and far between along the tracks.
2) More importantly is the wagon road. I've hiked much of it in the Granite area and for all intents and purposes it exists ABOVE the right of way and did not have grade crossings like the photo.
Though I have never been in Brown's Canyon, google imagery quickly reveals a narrower canyon with much more potential evidence of exposed bedding planes near the ROW. If we are to believe that the photo is of D&RG trackage along the Arkansas River, I would invest my time in trying to find a location in Brown's Canyon.