Why not develop a radar system able to detect objects that have fallen onto the tracks, automatically cutting power and notifying oncoming trains? The system will work by sending out a continuous spread of wideband radio waves and using an Automatic Target Recognition procedure to analyze the reflections of the waves when they will encounter a foreign object. The system is supposed to recognize a variety of objects, including suitcases, adults, and children.

Why not capture the kinetic energy of subway trains and use it to supplement the power the trains consume during startup. The system would operate through a variation of regenerative braking. A flywheel attached to the rail system would harness the energy of trains as they slow for a station, converting it to electrical power. The harnessed power could then be used to give the train a boost to get moving again.

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...

For decades, rag-pickers have been marching up and down the city's railway tracks gathering empty plastic bottles, wrappers and other garbage discarded by commuters. The solution for this has already been found in India. Central Railway engineers there modified an old engine into a massive trash can able to pull in all the garbage as it chugs along the tracks.