Can anybody help me to understand the bold text below? Not sure I comprehend it properly ...

“My brain grew as active as my body was inert. First I saw clearly the line stretching before me. I saw the rails shining in the moonlight. We were rushing along . . . how we tore along! . . . I became aware of the sensation of speed that habit had made me lose. The train passed a little station like a flash of lightning, but not too quickly for me to see a signalman dozing in his box near a telegraphic apparatus. A jolt or two on the turn-table; a clanging of plates; the line marked by rails that crossed each other, suddenly large, then small . . . the deep cutting, and once more the dash into darkness.
“Then came the tunnel into which we plunged like a raging hurricane . . . Once again the open line. Now I knew where we were, and I told myself we were bound to derail, that in two minutes we should come to a sharp curve, and that at the rate we were going at we were certain to bound off."

The 10:50 Express, Maurice Level, 1920