(svn r27862) [1.7] -Backport from trunk:

- Fix: Failed to load lzo compressed savegames sometimes [FS#6450] (r27793)
- Fix: [Win32] Mark OpenTTD as DPI-aware to avoid OS window scaling that breaks mouse input [FS#6366] (r27791, r27790)
- Fix: [NewGRF] Get vehicle load amount after executing new cargo trigger [FS#6536] (r27788)
- Fix: AI configuration changed incorrect parameter when some parameters are hidden [FS#6479] (r27787, r27786)
- Fix: Buoys not always drawn after being placed depending on zoom level [FS#6508] (r27785)
- Fix: Allow rail conversion even if ship is on tile [FS#6505] (r27784)

src/rail_cmd.cpp

@@ -1603,7 +1603,7 @@ CommandCost CmdConvertRail(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 		 * Tunnels and bridges have special check later */
 		if (tt != MP_TUNNELBRIDGE) {
 			if (!IsCompatibleRail(type, totype)) {
-				CommandCost ret = EnsureNoVehicleOnGround(tile);
+				CommandCost ret = IsPlainRailTile(tile) ? EnsureNoTrainOnTrackBits(tile, GetTrackBits(tile)) : EnsureNoVehicleOnGround(tile);
 				if (ret.Failed()) {
 					error = ret;
 					continue;