The car is self-operating, so use the wall-mounted phone to ring the mountainstation before boarding, then pay the 13 Swiss franc round-trip fare as you exit.
To beat the crowds, get an early start on your first day by staying overnight at mountainstation Kleine Scheidegg, the departure point for the Jungfraubahn, and catch the 8 am train.
Blink and you will miss Mazama (population 230), little more than a gas station, a cosy mountain inn and a mercantile store that, between November and April, is the last stop on the road west when Highway 20 across the North Cascades to Seattle is closed due to snow.