Index: src/road_cmd.cpp
===================================================================
--- src/road_cmd.cpp	(revisi¢n: 18520)
+++ src/road_cmd.cpp	(copia de trabajo)
@@ -697,9 +697,9 @@
 }

 /** Build a long piece of road.
- * @param end_tile end tile of drag
+ * @param end_tile start tile of drag
  * @param flags operation to perform
- * @param p1 start tile of drag
+ * @param p1 end tile of drag
  * @param p2 various bitstuffed elements
  * - p2 = (bit 0) - start tile starts in the 2nd half of tile (p2 & 1)
  * - p2 = (bit 1) - end tile starts in the 2nd half of tile (p2 & 2)
@@ -709,19 +709,20 @@
  * @param text unused
  * @return the cost of this operation or an error
  */
-CommandCost CmdBuildLongRoad(TileIndex end_tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
+CommandCost CmdBuildLongRoad(TileIndex start_tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	CommandCost cost(EXPENSES_CONSTRUCTION);
+	CommandCost ret, cost(EXPENSES_CONSTRUCTION);
 	bool had_bridge = false;
 	bool had_tunnel = false;
 	bool had_success = false;
+	bool inverted = false;
 	DisallowedRoadDirections drd = DRD_NORTHBOUND;

 	_error_message = INVALID_STRING_ID;

 	if (p1 >= MapSize()) return CMD_ERROR;

-	TileIndex start_tile = p1;
+	TileIndex end_tile = p1;
 	RoadType rt = (RoadType)GB(p2, 3, 2);
 	if (!IsValidRoadType(rt) || !ValParamRoadType(rt)) return CMD_ERROR;

@@ -729,11 +730,9 @@
 	if (!HasBit(p2, 2) && TileY(start_tile) != TileY(end_tile)) return CMD_ERROR; // x-axis
 	if (HasBit(p2, 2)  && TileX(start_tile) != TileX(end_tile)) return CMD_ERROR; // y-axis

-	/* Swap start and ending tile, also the half-tile drag var (bit 0 and 1) */
+	/* Swap the half-tile drag var (bit 0 and 1) */
 	if (start_tile > end_tile || (start_tile == end_tile && HasBit(p2, 0))) {
-		TileIndex t = start_tile;
-		start_tile = end_tile;
-		end_tile = t;
+		inverted = true;
 		p2 ^= IsInsideMM(p2 & 3, 1, 3) ? 3 : 0;
 		drd = DRD_SOUTHBOUND;
 	}
@@ -750,13 +749,18 @@
 	for (;;) {
 		RoadBits bits = HasBit(p2, 2) ? ROAD_Y : ROAD_X;

-		if (tile == end_tile && !HasBit(p2, 1)) bits &= ROAD_NW | ROAD_NE;
-		if (tile == start_tile && HasBit(p2, 0)) bits &= ROAD_SE | ROAD_SW;
+		if (inverted) {
+			if (tile == start_tile && !HasBit(p2, 1)) bits &= ROAD_NW | ROAD_NE;
+			if (tile == end_tile && HasBit(p2, 0)) bits &= ROAD_SE | ROAD_SW;
+		} else {
+			if (tile == end_tile && !HasBit(p2, 1)) bits &= ROAD_NW | ROAD_NE;
+			if (tile == start_tile && HasBit(p2, 0)) bits &= ROAD_SE | ROAD_SW;
+		}

 		_error_message = INVALID_STRING_ID;
-		CommandCost ret = DoCommand(tile, drd << 6 | rt << 4 | bits, 0, flags, CMD_BUILD_ROAD);
+		ret = DoCommand(tile, drd << 6 | rt << 4 | bits, 0, flags, CMD_BUILD_ROAD);
 		if (CmdFailed(ret)) {
-			if (_error_message != STR_ERROR_ALREADY_BUILT) return CMD_ERROR;
+			if (_error_message != STR_ERROR_ALREADY_BUILT) break;
 		} else {
 			had_success = true;
 			/* Only pay for the upgrade on one side of the bridges and tunnels */
@@ -779,7 +783,11 @@

 		if (tile == end_tile) break;

-		tile += HasBit(p2, 2) ? TileDiffXY(0, 1) : TileDiffXY(1, 0);
+		if (inverted) {
+			tile += HasBit(p2, 2) ? TileDiffXY(0, -1) : TileDiffXY(-1, 0);
+		} else {
+			tile += HasBit(p2, 2) ? TileDiffXY(0, 1) : TileDiffXY(1, 0);
+		}
 	}

 	return !had_success ? CMD_ERROR : cost;
Index: src/road_gui.cpp
===================================================================
--- src/road_gui.cpp	(revisi¢n: 18520)
+++ src/road_gui.cpp	(copia de trabajo)
@@ -605,7 +605,7 @@
 					 * not the 3rd bit set) */
 					_place_road_flag = (RoadFlags)((_place_road_flag & RF_DIR_Y) ? (_place_road_flag & 0x07) : (_place_road_flag >> 3));

-					DoCommandP(end_tile, start_tile, _place_road_flag | (_cur_roadtype << 3) | (_one_way_button_clicked << 5),
+					DoCommandP(start_tile, end_tile, _place_road_flag | (_cur_roadtype << 3) | (_one_way_button_clicked << 5),
 						_remove_button_clicked ?
 						CMD_REMOVE_LONG_ROAD | CMD_MSG(_road_type_infos[_cur_roadtype].err_remove_road) :
 						CMD_BUILD_LONG_ROAD | CMD_MSG(_road_type_infos[_cur_roadtype].err_build_road), CcPlaySound1D);