Perhaps even as we speak he's lying with his head on the metals, an unresisting prey to any passing express--" "Oh, don't try to talk like a book," cried Bobbie, bolting what was left of her sandwich; "come on.

Phil, keep close behind me, and if a train comes, stand flat against the tunnel wall and hold your petticoats close to you." "Give me one more sandwich," pleaded Phyllis, "and I will." "I'm going first," said Peter; "it was my idea," and he went.
Of course you know what going into a tunnel is like?
The engine gives a scream and then suddenly the noise of the running, rattling train changes and grows different and much louder.

Grown-up people pull up the windows and hold them by the strap.

The railway carriage suddenly grows like night--with lamps, of course, unless you are in a slow local train, in which case lamps are not always provided.

Then by and by the darkness outside the carriage window is touched by puffs of cloudy whiteness, then you see a blue light on the walls of the tunnel, then the sound of the moving train changes once more, and you are out in the good open air again, and grown-ups let the straps go.