Les Balcons du Tet is a popular shuttle route in this region of France. If the train isn't broken down, you can take a train up the vast majority of the climb, finish the climb on pavement and gravel, and then bomb down this excellent singletrack trail. Alternatively, you can do a van shuttle, as I did with MTB dreams.
The upper portion of the trail is steep, fast, and pretty technical, with some gorgeous views.
Lower done, you reach the "Balcons," a bench cut section of trail made with stone wall shoring up the bottom side of it.