The train is slowed by the climb, and then leaves down a slope, so kinetic energy is converted to gravitational potential energy in the station. (en.m.wikipedia.org)
While this happens, massive bursts of energy — the result of the conversion of gravitational potential energy into radiation — are being released. (ibtimes.com)
The authors study whether or not such planets can be habitable, noting this key fact about brown dwarf evolution: The brown dwarf is continually fading as it releases gravitational potential energy. (centauri-dreams.org)