Index: src/tunnelbridge_cmd.cpp
===================================================================
--- src/tunnelbridge_cmd.cpp	(revision 20829)
+++ src/tunnelbridge_cmd.cpp	(working copy)
@@ -582,15 +582,23 @@
 
 	/* slope of end tile must be complementary to the slope of the start tile */
 	if (end_tileh != ComplementSlope(start_tileh)) {
-		/* Check if there is a structure on the terraformed tile. Do not add the cost, that will be done by the terraforming
-		 * Note: Currently the town rating is also affected by this clearing-test. So effectivly the player is punished twice for clearing
-		 *       the tree on end_tile.
-		 */
-		ret = DoCommand(end_tile, 0, 0, DC_AUTO, CMD_LANDSCAPE_CLEAR);
-		if (ret.Failed()) return_cmd_error(STR_ERROR_UNABLE_TO_EXCAVATE_LAND);
+		/* We need to perform two things here.
+		 *  1) Clear the tile including any associated tiles of multitile objects.
+		 *  2) Terraform the tile including surrounding tiles.
+		 * Unfortunatelly 2) also clears the tile in some cases (e.g. trees), but not all.
+		 * So during the testrun both commands cost money and townrating while we cannot tell
+		 * what share of that cost is a duplicate between 1) and 2).
+		 * To properly replay the command during DC_EXEC we first estimate the cost for clearing,
+		 * then do the terraforming, and finally force-clear whatever there is left.
+		 * This will result in doubled cost of both money and townrating when clearing trees or
+		 * auto-removable objects etc.. */
+		cost.AddCost(DoCommand(end_tile, 0, 0, flags & ~DC_EXEC, CMD_LANDSCAPE_CLEAR));
+		if (cost.Failed()) return_cmd_error(STR_ERROR_UNABLE_TO_EXCAVATE_LAND);
 
 		ret = DoCommand(end_tile, end_tileh & start_tileh, 0, flags, CMD_TERRAFORM_LAND);
 		if (ret.Failed()) return_cmd_error(STR_ERROR_UNABLE_TO_EXCAVATE_LAND);
+
+		DoCommand(end_tile, 0, 0, flags | DC_NO_MODIFY_TOWN_RATING | DC_NO_TEST_TOWN_RATING, CMD_LANDSCAPE_CLEAR);
 	} else {
 		ret = DoCommand(end_tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 		if (ret.Failed()) return ret;