--- a/src/date.cpp	Thu Apr 03 21:01:01 2008 +0000
+++ b/src/date.cpp	Thu Apr 03 21:54:31 2008 +0000
@@ -15,6 +15,7 @@
 #include "date_func.h"
 #include "vehicle_base.h"
 #include "debug.h"
+#include "rail_gui.h"
 #ifdef DEBUG_DUMP_COMMANDS
 #include "saveload.h"
 #endif
@@ -282,6 +283,8 @@
 	ShipsYearlyLoop();
 	if (_network_server) NetworkServerYearlyLoop();
 
+	if (_cur_year == _patches.semaphore_build_before) ResetSignalVariant();
+
 	/* check if we reached end of the game */
 	if (_cur_year == _patches.ending_year) {
 			ShowEndGameChart();

--- a/src/misc_gui.cpp	Thu Apr 03 21:01:01 2008 +0000
+++ b/src/misc_gui.cpp	Thu Apr 03 21:54:31 2008 +0000
@@ -41,6 +41,7 @@
 #include "player_gui.h"
 #include "settings_type.h"
 #include "newgrf_cargo.h"
+#include "rail_gui.h"
 
 #include "table/sprites.h"
 #include "table/strings.h"
@@ -1833,6 +1834,7 @@
 	SetDate(ConvertYMDToDate(_cur_year + p2, ymd.month, ymd.day));
 	EnginesMonthlyLoop();
 	SetWindowDirty(FindWindowById(WC_STATUS_BAR, 0));
+	ResetSignalVariant();
 	return _cur_year;
 }
 

--- a/src/openttd.cpp	Thu Apr 03 21:01:01 2008 +0000
+++ b/src/openttd.cpp	Thu Apr 03 21:54:31 2008 +0000
@@ -93,7 +93,7 @@
 extern void SetDifficultyLevel(int mode, GameOptions *gm_opt);
 extern Player* DoStartupNewPlayer(bool is_ai);
 extern void ShowOSErrorBox(const char *buf);
-extern void SetDefaultRailGui();
+extern void InitializeRailGUI();
 
 /* TODO: usrerror() for errors which are not of an internal nature but
  * caused by the user, i.e. missing files or fatal configuration errors.
@@ -702,7 +702,7 @@
 	DoCommandP(0, (_patches.autorenew << 15 ) | (_patches.autorenew_months << 16) | 4, _patches.autorenew_money, NULL, CMD_SET_AUTOREPLACE);
 
 	SettingsDisableElrail(_patches.disable_elrails);
-	SetDefaultRailGui();
+	InitializeRailGUI();
 
 #ifdef ENABLE_NETWORK
 	/* We are the server, we start a new player (not dedicated),
@@ -1997,7 +1997,7 @@
 	if (CheckSavegameVersion(38)) _patches.disable_elrails = false;
 	/* do the same as when elrails were enabled/disabled manually just now */
 	SettingsDisableElrail(_patches.disable_elrails);
-	SetDefaultRailGui();
+	InitializeRailGUI();
 
 	/* From version 53, the map array was changed for house tiles to allow
 	 * space for newhouses grf features. A new byte, m7, was also added. */

--- a/src/rail_gui.cpp	Thu Apr 03 21:01:01 2008 +0000
+++ b/src/rail_gui.cpp	Thu Apr 03 21:54:31 2008 +0000
@@ -45,9 +45,9 @@
 static DiagDirection _build_depot_direction;
 static byte _waypoint_count = 1;
 static byte _cur_waypoint_type;
-static bool _convert_signal_button = false;              ///< convert signal button in the signal GUI pressed
-static SignalVariant _cur_signal_variant = SIG_ELECTRIC; ///< set the signal variant (for signal GUI)
-static SignalType _cur_signal_type = SIGTYPE_NORMAL;     ///< set the signal type (for signal GUI)
+static bool _convert_signal_button;       ///< convert signal button in the signal GUI pressed
+static SignalVariant _cur_signal_variant; ///< set the signal variant (for signal GUI)
+static SignalType _cur_signal_type;       ///< set the signal type (for signal GUI)
 
 static struct {
 	byte orientation;
@@ -1385,14 +1385,9 @@
 
 /**
  * Open the signal selection window
- * @pre reset all signal GUI relevant variables
  */
 static void ShowSignalBuilder()
 {
-	_convert_signal_button = false;
-	_cur_signal_variant = _cur_year < _patches.semaphore_build_before ? SIG_SEMAPHORE : SIG_ELECTRIC;
-	_cur_signal_type = SIGTYPE_NORMAL;
-
 	AllocateWindowDesc(&_signal_builder_desc);
 }
 
@@ -1601,7 +1596,7 @@
 	MarkWholeScreenDirty();
 }
 
-void SetDefaultRailGui()
+static void SetDefaultRailGui()
 {
 	if (_local_player == PLAYER_SPECTATOR || !IsValidPlayer(_local_player)) return;
 
@@ -1650,5 +1645,36 @@
 	}
 }
 
+/**
+ * Updates the current signal variant used in the signal GUI
+ * to the one adequate to current year.
+ * @param 0 needed to be called when a patch setting changes
+ * @return success, needed for patch settings
+ */
+int32 ResetSignalVariant(int32 = 0)
+{
+	SignalVariant new_variant = (_cur_year < _patches.semaphore_build_before ? SIG_SEMAPHORE : SIG_ELECTRIC);
 
+	if (new_variant != _cur_signal_variant) {
+		Window *w = FindWindowById(WC_BUILD_SIGNAL, 0);
+		if (w != NULL) {
+			SetWindowDirty(w);
+			w->RaiseWidget((_cur_signal_variant == SIG_ELECTRIC ? BSW_ELECTRIC_NORM : BSW_SEMAPHORE_NORM) + _cur_signal_type);
+		}
+		_cur_signal_variant = new_variant;
+	}
 
+	return 0;
+}
+
+/** Resets the rail GUI - sets default railtype to build
+ * and resets the signal GUI
+ */
+void InitializeRailGUI()
+{
+	SetDefaultRailGui();
+
+	_convert_signal_button = false;
+	_cur_signal_type = SIGTYPE_NORMAL;
+	ResetSignalVariant();
+}

--- a/src/rail_gui.h	Thu Apr 03 21:01:01 2008 +0000
+++ b/src/rail_gui.h	Thu Apr 03 21:54:31 2008 +0000
@@ -9,5 +9,6 @@
 
 void ShowBuildRailToolbar(RailType railtype, int button);
 void ReinitGuiAfterToggleElrail(bool disable);
+int32 ResetSignalVariant(int32 = 0);
 
 #endif /* RAIL_GUI_H */

--- a/src/settings.cpp	Thu Apr 03 21:01:01 2008 +0000
+++ b/src/settings.cpp	Thu Apr 03 21:54:31 2008 +0000
@@ -51,6 +51,7 @@
 #include "transparency.h"
 #include "textbuf_gui.h"
 #include "string_func.h"
+#include "rail_gui.h"
 #include "gui.h"
 #include "town.h"
 #include "video/video_driver.hpp"
@@ -1404,7 +1405,7 @@
 	SDT_BOOL(Patches, always_small_airport,          0,NN, false,        STR_CONFIG_PATCHES_SMALL_AIRPORTS,      NULL),
 	SDT_BOOL(Patches, enable_signal_gui,             S, 0, false,        STR_CONFIG_PATCHES_ENABLE_SIGNAL_GUI,   NULL),
 	 SDT_VAR(Patches, drag_signals_density,SLE_UINT8,S, 0,  4, 1, 20, 0, STR_CONFIG_PATCHES_DRAG_SIGNALS_DENSITY,NULL),
-	 SDT_VAR(Patches, semaphore_build_before,SLE_INT32, S, NC, 1975, MIN_YEAR, MAX_YEAR, 1, STR_CONFIG_PATCHES_SEMAPHORE_BUILD_BEFORE_DATE, NULL),
+	 SDT_VAR(Patches, semaphore_build_before,SLE_INT32, S, NC, 1975, MIN_YEAR, MAX_YEAR, 1, STR_CONFIG_PATCHES_SEMAPHORE_BUILD_BEFORE_DATE, ResetSignalVariant),
 	SDT_CONDVAR(Patches, town_layout, SLE_UINT8, 59, SL_MAX_VERSION, 0, MS, TL_ORIGINAL, TL_NO_ROADS, NUM_TLS - 1, 1, STR_CONFIG_PATCHES_TOWN_LAYOUT, CheckTownLayout),
 
 	/***************************************************************************/