Puzzle Playland

Two trains race toward each other on a railway segment that's 100 miles long. The trains are traveling at 100mph. An insect flying at 200mph flits from one train toward the other, and as soon as it arrives at the other, it flips its direction and flies back toward the first train. The insect continues bouncing back and forth between the trains until the trains crash. What's the total distance that the insect covers until the moment of the crash?