The portage around the collapsed tunnel is an unimproved hiking trail and will be difficult for kids and older adults. I was constantly in the lower two gears of my mountain bike, and uphill averaged 4 mph with breaks. The steep grade, high altitude and loose material make the trail challenging for casual riders. I have ridden rail trails in 42 states and this one is the steepest I have encountered, probably because it was a narrow gauge railway. This trail is not suitable for kids and occasional riders because of the loose material and steep grade. Trail surface is mostly loose gravel, there is usually one track on the side that is firm enough to ride on.
This is a fine trail for hiking, but not for biking.
