Modern trains use heat to kill cabin noise

As modern night trains race across Europe at 200 kilometers per hour, the loudest sound isn't the engine but the high-pitched singing of steel wheels against the track. These microscopic imperfections in the rail vibrate the carriage at frequencies reaching several thousand hertz, creating a persistent hum that can keep passengers awake. While early 20th-century luxury sleepers relied on the sheer weight of heavy timber and thick wool carpets to muffle noise, today's energy-efficient cars use a more elegant solution rooted in materials science.