Around The World in Eighty Days by Jules Verne Chapter 29 Page 13

outside, shut them in. They were to begin firing at the first whistle of the locomotive. After an interval of two minutes, what remained of the two gentlemen would be taken from the car.

Nothing could be more simple. Indeed, it was all so simple that Fix and Passepartout felt their hearts beating as if they would crack. They were listening for the whistle agreed upon, when suddenly savage cries resounded in the air, accompanied by reports which certainly did not issue from the car where the duellists were. The reports continued in front and the whole length of the train. Cries of terror proceeded from the interior of the cars.

Colonel Proctor and Mr. Fogg, revolvers in hand, hastily quitted their prison, and rushed forward where the noise was most clamorous. They then perceived that the train was attacked by a band of Sioux.