Edward Whymper,
Scrambles amongst the Alps — Chapter 3
(1871)
“ In a few yards its pace is reduced, and it comes down and down to about four miles an hour, which speed is usually maintained until the incline is passed, without a diminution of the steam-pressure. I say usually, because, if it should happen that there is not sufficient steam, or should the driver happen to make a slip, the train would most likely come back to Modane; for, although the break-power on the train is much more than sufficient to prevent it running back, the driver could hardly start with the breaks on, and the train would inevitably run back if they were off. ”
