The road led north, back to Argentina. The frontier was at Caracoles, ten ten thousand feet up, and there was one road across the mountain pass to Mendoza, but it was closed to traffic by the Chilean frontier guards. The only way through was by the railway tunnel. I waited for two hours, with a growing company of cars and trucks, until the oncoming train from Argentina had passed. Then I was sent in ahead of the four-wheeled traffic.
The tunnel was three kilometres long, an unlined hole through the living rock. Boards had been laid on either side of one rail, but I was warned to stay to the right, between the rail and the rock face.
There was no lighting. The rocks dripped water on me and on the boards which were slippery with mud. I moved, painfully slow, through the gloom, aware of the car behind me which always seemed to be too close. Again and again I felt my rear wheel slip and slide out of control until at one point I was almost certain that the tyre was punctured, and I wondered how to choose between the twin horrors of risking an accident or trying to repair a tyre.
I went on and on, and on, interminably creeping through that foul hole until, at last, I saw a faint glimmer ahead. Never have I been more glad to see the light at the end of a tunnel. I came out into a glorious valley and as I sped along beside a tumbling mountain stream it became ever more beautiful, ever more enticing. The valley broadened and deepened and my spirits, released from the dark tunnel, expanded and soared, and I was away and on the road and flying again.
Riding High Ted Simon pp275-6