Water Troughs These troughs allowed train crews to replenish the water supplies of their locomotives without having to stop the train. As the locomotive reached the start of the water trough (usually indicated by a track side marker board), the fireman would lower a scoop into the trough.

Steam engines required massive amounts of water to generate power, and engineers developed several ingenious systems to ensure they didn't run dry on long journeys. The most common method was the use of water stops, where trains would pause every 7–15 miles at specialized water towers or tanks to refill their tenders. To save time on express routes, railways installed water troughs (also known as track pans) between the rails; as the train sped over these long, shallow troughs, a mechanical "scoop" was lowered from the tender to force water up into the tank using the train's own momentum. For locomotives operating in arid regions or tunnels, condensers were sometimes used to catch exhausted steam, cool it back into liquid water, and reuse it, though this was less common due to complexity. By 2026, these historic systems are mostly seen on heritage railways, but they remain a testament to the heavy infrastructure of dams, reservoirs, and pumping stations that were once necessary to keep the global rail network hydrated and moving.