The line stops at
22 metres per second.
Every operator says the line stops when it is unsafe. That is not a commitment, it is a mood. Below are the five thresholds the machine room is held to, the number attached to each, and what happens when it is reached — so a passenger standing at the barrier in a gale knows what is being decided and on what.
| Measured at | What is measured | Threshold | What happens |
|---|---|---|---|
| Tower IV | Sustained wind | 22 m/s | Line stops. Cars are run in and parked at the stations. |
| Tower IV | Gust | 28 m/s | Line stops immediately, cars evacuated to the nearest station. |
| Line | Rime on the rope | 12 mm radial | De-icing haul at 1.5 m/s before passengers are carried. |
| Line | Visibility at the top | under 60 m | Descent only. No ascents sold. |
| Line | Lightning within | 8 km | Line stops. The towers are the tallest thing on the ridge. |
Tower IV carries the anemometer because it is the exposed one — the saddle funnels there and it reads three to five metres per second above the base station in the same weather. A hold called on Tower IV is a hold called on the worst place on the line, which is the point.
The record, in numbers we publish
The haul rope is magnetically scanned end to end every autumn and the grips are pull-tested on a rolling twelve-week cycle. Two cars come off the rope every night for that test, which is why the fleet is 24 and the interval is set for 22.
If the line stops with you on it
- 01
Stay seated. A stopped cabin is a cabin hanging still on a 46 mm rope; nothing about the stop is a fault in the thing holding you.
- 02
The intercom in the door pillar reaches the machine room directly and is tested every morning on the empty haul.
- 03
The line restarts on the diesel drive if the mains fail. Changeover is tested monthly and takes under four minutes.
- 04
If the rope cannot be driven at all, cars are recovered from the ground by rope crew, tower to tower, from the downhill end. The full line is rehearsed twice a season.