The conductor regarded the boy with surprise. "Do you mean you will join us to help capture the bandits?" "What do you think we're here for?" asked Billie. "Yes," chimed in Adrian. "What do you suppose we stopped the train for?" "But even ten are no match for twenty or more," declared the guard. "Of course they are," said Donald, "if the twenty are taken by surprise." "Which they will not be if we don't act pretty quick," insisted Billie. "Come on! Let's go after them," and he climbed up onto the car. "That's what I say," said Pedro, following Billie's example. Without more words the others followed and the conductor gave the signal to go ahead. "How about the horses?" asked Donald, turning to Pedro. "They'll be all right; but if we capture the Zapatistas we'll have horses enough any way." "And if we don't," remarked Billie grimly, "there'll be some riderless horses any way." "Let us hope that they will not be the ones we have left behind," said Donald gravely. CHAPTER II. A STRANGE MIX-UP. While the train was gathering headway the conductor and the guards rounded up all the men they could find on the train who were armed. There were more than a dozen, so that in point of numbers, the force on the train nearly equalled the Zapatistas. These were so stationed at the windows that they could give the would-be robbers a warm reception. "We must use some strategy," declared Adrian, "or we will simply succeed in killing a few and scaring away the others. That will not be a very brilliant deed." "No," from Donald, "but it will save the bullion. What's your plan?" "Well, I was thinking it would be a good plan to separate the train." "How?" "You can see it is all down grade from here to where the bandits are waiting for us." "Yes." "As soon as we get to running a good speed, Billie and I will go into the express car with the three guards. You and Pedro stay here with the other guards and the passengers. As we near the bandits, uncouple the train, put on the brakes and stop the coaches. We will rush by with the engine and express car, firing as we go----" "Which will be all right," interrupted Billie, "if they don't ditch the engine." Adrian's face fell. "I hadn't thought of that." "Well, you'd better." After a moment Adrian's face brightened. "They might better ditch the engine and express car than the whole train," he declared. "Right you are," from Donald. "If you and Billie are game enough to try it, I say it is the proper thing. If they ditch the engine, we will be back a ways and can run down to your assistance. If they don't ditch you, we will have them between two fires." "Just what I thought," replied Adrian. "How about it, Billie?" "I'm game. My head may be a little thick, but I can see just as far through a two-inch plank as the next one."