My idea is to capture the wind a train generates as it speeds down the track, using that untapped force to create electricity. Several devices would be placed between the rails of either railway or subway lines. Each device would contain a turbine to gather the otherwise wasted wind energy and harnesses it to produce electricity. The cylindrical devices would be installed on the tracks below ground level on busy rail lines, where they should be able to gather enough wind to...

Why not use magma as a potential source of geothermal energy? It is actually able to power up to 30,000 homes. FYI, magma can produce dry steam at 750 degrees Fahrenheit, which can generate up to 25 megawatts of electricity. The usual geothermal well can produce 5 to 8 megawatts of electricity.