The strava segment linked above does not have fast times because it is a bicycle segment instead of a run segment. There are many running segments on the site, but none cover the exactly right distance from gate to summit. However, on October 31, 2017, I completed the ascent from gate to summit in 49:11. https://www.strava.com/activities/1255583974
Route: Mailbox Peak (WA)
Mailbox Peak (4822') is a very popular hike near North Bend, WA.
The old trail up Mailbox Peak was the stuff of legend. It inspired potential Rainier climbers, challenged adventurous day hikers, and occasionally Mother Nature used the trail to bite back. The number of injuries and rescues on the old trail, as well as terrible erosion caused by the masses of daily visitors, prompted the Department of Natural Resources to create a new trail to the top. While still relatively steep, this new route, built in part by WTA volunteers, offers a safer way for folks to attain the summit of this formidable peak. The new trail is about 9.4 miles round trip, vs. 5.4 miles for the old trail. Either way you gain 4000'. The old trail has a Strava segment (shown on our map).
This article indicates that Uli Steidl did Mailbox in 54m33s up and 33m00s down (total of 1h27m33s, but does not say if additional time was spent on top) in 2010. This was presumably on the old trail, and is quite a bit faster than anything currently on Strava.
I'm tentatively planning to climb the new trail (gate-to-gate) this Sunday, pending travel plans working out and the air quality staying good.