Quintana 39:22 in 2015 (and 39:48 in 2013).Not sure how you can possibly compare a sub 3 minute climb with a 40 minute climb?? Mur de Huy requires different energy system - it is hugely anaerobic. The Alpe is purely aerobic. As far as I can research, nobody has ridden sub 40 minutes on the Alpe for years now. In 2018 Thomas was untouchable by any rival climbers after being towed from the bottom by the might of the Sky train in full flight and still only did something like 41 minutes.
Alpe d'Huez: Quintana super fast and Croix de Fer record!
Col de la Croix de Fer 2015:28,5 km km@5,2%---1:07:53---average speed 25.19 km/h(Quintana-Valverde)-RECORD ...
www.climbing-records.com