How do chairlift seats get heated up?

My grandson is interested by technology and when he skis with me, by all the ski lifts we ride. One day, he asked me how the heating system on one of the chairlift we regularly use, works. 

The one in question is at Canyons, in Park City, and has been in operation since 2010. It is also equipped with a protection bubble that can further protect skiers against cold winds, frequent in that area. 

Made by Doppelmayr, this chairlift with heated seats has been launched in 2004 and is now in service on over 225 lifts worldwide. 

When the chair gets to the bottom station, two power rails bring the electrical current for 15 to 20 seconds, through friction, into the detachable grip assembly, and then to resistances placed inside the seat to warm it temporarily as skiers take place on the chair. 

The power flow stops once the chair leaves the station and dissipates into heat through the seating pad that’s heated enough (420 W per seat) to provide the passengers with some comforting warmth through the first few minutes of their trip. 

 

In terms of reliability, we can generously say that the one we regularly ride works 60% of the time, which is better than nothing, but probably not worth the enormous extra expense involved!