The itinerary lasts 3hrs 09min, and has 2 steps.

Lyon - Grenoble
The step from Lyon to Grenoble lasts 1hrs 24min. You'll travel in a regional train.

Grenoble - L'Alpe d'Huez
The step from Grenoble to L'Alpe d'Huez lasts 1hrs 45min. You'll travel in a day bus.