Alien Express

A new bullet train is speeding passengers to Las Vegas, along with a U.S. Senator from Texas running for president, when a meteorite crashes into a car near the tracks, releasing a tiny creature. The train stops to survey the damage, and the police are called. This stop allows the creature to board the train before it once again speeds off. Once it kills and consumes everyone aboard the train, it begins to grow and multiply into many differing creatures.