Index: src/rail.h
===================================================================
--- src/rail.h	(revision 27841)
+++ src/rail.h	(working copy)
@@ -26,10 +26,12 @@
 enum RailTypeFlags {
 	RTF_CATENARY          = 0,                           ///< Bit number for drawing a catenary.
 	RTF_NO_LEVEL_CROSSING = 1,                           ///< Bit number for disallowing level crossings.
+	RTF_HIDE_CONSTRUCTION = 2,                           ///< Bit number for hiding from construction.
 
 	RTFB_NONE              = 0,                          ///< All flags cleared.
 	RTFB_CATENARY          = 1 << RTF_CATENARY,          ///< Value for drawing a catenary.
 	RTFB_NO_LEVEL_CROSSING = 1 << RTF_NO_LEVEL_CROSSING, ///< Value for disallowing level crossings.
+	RTFB_HIDE_CONSTRUCTION = 1 << RTF_HIDE_CONSTRUCTION, ///< Value for hiding from construction.
 };
 DECLARE_ENUM_AS_BIT_SET(RailTypeFlags)
 
Index: src/rail_cmd.cpp
===================================================================
--- src/rail_cmd.cpp	(revision 27841)
+++ src/rail_cmd.cpp	(working copy)
@@ -169,8 +169,8 @@
 			rti->powered_railtypes    = (RailTypes)(1 << rt);
 			rti->compatible_railtypes = (RailTypes)(1 << rt);
 
-			/* We also introduce ourself. */
-			rti->introduces_railtypes = (RailTypes)(1 << rt);
+			/* We also introduce ourself if not hidden. */
+			if (!HasBit(rti->flags, RTF_HIDE_CONSTRUCTION)) rti->introduces_railtypes = (RailTypes)(1 << rt);
 
 			/* Default sort order; order of allocation, but with some
 			 * offsets so it's easier for NewGRF to pick a spot without