--- a/src/rail_cmd.cpp	Sun Apr 01 10:55:31 2007 +0000
+++ b/src/rail_cmd.cpp	Sun Apr 01 11:11:49 2007 +0000
@@ -254,7 +254,7 @@
 	switch (GetTileType(tile)) {
 		case MP_RAILWAY:
 			if (!CheckTrackCombination(tile, trackbit, flags) ||
-					!EnsureNoVehicle(tile)) {
+					!EnsureNoVehicleOnGround(tile)) {
 				return CMD_ERROR;
 			}
 			if (!IsTileOwner(tile, _current_player) ||
@@ -289,7 +289,7 @@
 			}
 #undef M
 
-			if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+			if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
 			if (GetRoadTileType(tile) == ROAD_TILE_NORMAL) {
 				if (HasRoadWorks(tile)) return_cmd_error(STR_ROAD_WORKS_IN_PROGRESS);
@@ -352,7 +352,7 @@
 			if (!IsLevelCrossing(tile) ||
 					GetCrossingRailBits(tile) != trackbit ||
 					(_current_player != OWNER_WATER && !CheckTileOwnership(tile)) ||
-					!EnsureNoVehicle(tile)) {
+					!EnsureNoVehicleOnGround(tile)) {
 				return CMD_ERROR;
 			}
 
@@ -367,7 +367,7 @@
 
 			if (!IsPlainRailTile(tile) ||
 					(_current_player != OWNER_WATER && !CheckTileOwnership(tile)) ||
-					!EnsureNoVehicle(tile)) {
+					!EnsureNoVehicleOnGround(tile)) {
 				return CMD_ERROR;
 			}
 
@@ -623,7 +623,7 @@
 	SignalVariant sigvar = (pre_signal ^ HASBIT(p1, 4)) ? SIG_SEMAPHORE : SIG_ELECTRIC;
 	int32 cost;
 
-	if (!ValParamTrackOrientation(track) || !IsTileType(tile, MP_RAILWAY) || !EnsureNoVehicle(tile))
+	if (!ValParamTrackOrientation(track) || !IsTileType(tile, MP_RAILWAY) || !EnsureNoVehicleOnGround(tile))
 		return CMD_ERROR;
 
 	/* Protect against invalid signal copying */
@@ -810,7 +810,7 @@
 
 	if (!ValParamTrackOrientation(track) ||
 			!IsTileType(tile, MP_RAILWAY) ||
-			!EnsureNoVehicle(tile) ||
+			!EnsureNoVehicleOnGround(tile) ||
 			!HasSignalOnTrack(tile, track)) {
 		return CMD_ERROR;
 	}
@@ -867,7 +867,7 @@
 
 	if (GetRailType(tile) == totype) return CMD_ERROR;
 
-	if (!EnsureNoVehicle(tile) && (!IsCompatibleRail(GetRailType(tile), totype) || IsPlainRailTile(tile))) return CMD_ERROR;
+	if (!EnsureNoVehicleOnGround(tile) && (!IsCompatibleRail(GetRailType(tile), totype) || IsPlainRailTile(tile))) return CMD_ERROR;
 
 	// 'hidden' elrails can't be downgraded to normal rail when elrails are disabled
 	if (_patches.disable_elrails && totype == RAILTYPE_RAIL && GetRailType(tile) == RAILTYPE_ELECTRIC) return CMD_ERROR;
@@ -971,7 +971,7 @@
 	if (!CheckTileOwnership(tile) && _current_player != OWNER_WATER)
 		return CMD_ERROR;
 
-	if (!EnsureNoVehicle(tile))
+	if (!EnsureNoVehicleOnGround(tile))
 		return CMD_ERROR;
 
 	if (flags & DC_EXEC) {

--- a/src/road_cmd.cpp	Sun Apr 01 10:55:31 2007 +0000
+++ b/src/road_cmd.cpp	Sun Apr 01 11:11:49 2007 +0000
@@ -120,7 +120,7 @@
 
 	if (!CheckAllowRemoveRoad(tile, pieces, &edge_road)) return CMD_ERROR;
 
-	if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+	if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
 	/* check if you're allowed to remove the street owned by a town
 	 * removal allowance depends on difficulty setting */
@@ -281,7 +281,7 @@
 					if ((existing & pieces) == pieces) {
 						return_cmd_error(STR_1007_ALREADY_BUILT);
 					}
-					if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+					if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 					break;
 
 				case ROAD_TILE_CROSSING:
@@ -325,7 +325,7 @@
 				default: goto do_clear;
 			}
 
-			if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+			if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
 			if (flags & DC_EXEC) {
 				YapfNotifyTrackLayoutChange(tile, FindFirstTrack(GetTrackBits(tile)));
@@ -383,7 +383,7 @@
 	if (!IsLevelCrossing(tile)) return CMD_ERROR;
 
 	/* not owned by me? */
-	if (!CheckTileOwnership(tile) || !EnsureNoVehicle(tile)) return CMD_ERROR;
+	if (!CheckTileOwnership(tile) || !EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
 	if (GetRailType(tile) == totype) return CMD_ERROR;
 
@@ -902,7 +902,7 @@
 			if (t->road_build_months != 0 &&
 					(DistanceManhattan(t->xy, tile) < 8 || grp != 0) &&
 					GetRoadTileType(tile) == ROAD_TILE_NORMAL && (GetRoadBits(tile) == ROAD_X || GetRoadBits(tile) == ROAD_Y)) {
-				if (GetTileSlope(tile, NULL) == SLOPE_FLAT && EnsureNoVehicle(tile) && CHANCE16(1, 20)) {
+				if (GetTileSlope(tile, NULL) == SLOPE_FLAT && EnsureNoVehicleOnGround(tile) && CHANCE16(1, 20)) {
 					StartRoadWorks(tile);
 
 					SndPlayTileFx(SND_21_JACKHAMMER, tile);

--- a/src/tunnelbridge_cmd.cpp	Sun Apr 01 10:55:31 2007 +0000
+++ b/src/tunnelbridge_cmd.cpp	Sun Apr 01 11:11:49 2007 +0000
@@ -637,8 +637,8 @@
 
 	endtile = GetOtherBridgeEnd(tile);
 
-	if (!EnsureNoVehicle(tile) ||
-			!EnsureNoVehicle(endtile) ||
+	if (!EnsureNoVehicleOnGround(tile) ||
+			!EnsureNoVehicleOnGround(endtile) ||
 			IsVehicleOnBridge(tile, endtile, GetBridgeHeight(tile))) {
 		return CMD_ERROR;
 	}
@@ -741,8 +741,8 @@
 
 		endtile = GetOtherBridgeEnd(tile);
 
-		if (!EnsureNoVehicle(tile) ||
-				!EnsureNoVehicle(endtile) ||
+		if (!EnsureNoVehicleOnGround(tile) ||
+				!EnsureNoVehicleOnGround(endtile) ||
 				IsVehicleOnBridge(tile, endtile, GetBridgeHeight(tile))) {
 			return CMD_ERROR;
 		}