Funival

The Funival starts above ground in La Daille and after a few hundred meters it enters a tunnel ending at the mountain station on top of the Bellevarde.
The Funival uses two trains, connected by cables, on a single track. Halfway, a short section of dual track allows the trains to pass each other.
A single track starts in La Daille from where the train runs up an elevated track for 580 m . The remaining 1,720 m . runs through a drilled tunnel. Halfway a section of double track allows the climbing train to pass the downward train. A cable runs from the front of the lower train, via a construction of electric powered pulleys in the mountain station to the back of the descending train. The mass of the descending train helps pull the climbing train and electric motors provide the power to overcome the weight difference between the climbing and descending trains plus any friction.

Wikipedia