diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -1588,6 +1588,7 @@ CommandCost CmdConvertRail(TileIndex til
 		}
 	}
 
+	delete iter;
 	return (cost.GetCost() == 0) ? error : cost;
 }