Railway environments present a rich but challenging source of energy harvesting opportunities, thanks to the substantial vibrations, shocks and dynamic loads induced by passing trains and infrastructure deformations. To exploit this energy for powering low-power sensor systems in trackside or onboard applications, a nonlinear approach, namely a bistable energy harvester—offers a promising alternative to conventional linear resonant devices. A bistable harvester employs a mechanical system with two stable equilibrium positions separated by a potential barrier. Under sufficiently large external excitation, the system “jumps” between the two wells, achieving comparatively large amplitude motion and thereby generating more electrical energy over a broader frequency bandwidth. Compared to narrow-band linear harvesters, bistable designs are better suited to the broad, stochastic, and variable vibration spectra typical of railway conditions. The Bistable Piezoelectric Energy Harvester (BPEH) has been designed, tested in lab and installed in railways to monitor the harvested energy.