2. The Aerotrain

The Aerotrain, launched by General Motors in the 1950s, was designed to make rail travel sleek and modern once again. Its lightweight, futuristic cars promised efficiency, but the reality included rough rides and an inability to handle steep tracks. Passengers were unimpressed, and railroads quickly retired the trains. Unlike the high-speed successes in Europe, the Aerotrain vanished into history. Read more at Amtrak History.