Index: lang/english.txt
===================================================================
--- lang/english.txt	(revision 7559)
+++ lang/english.txt	(working copy)
@@ -1038,6 +1038,7 @@
 STR_CONFIG_PATCHES_BRIBE                                        :{LTBLUE}Allow bribing of the local authority: {ORANGE}{STRING1}
 STR_CONFIG_PATCHES_NONUNIFORM_STATIONS                          :{LTBLUE}Nonuniform stations: {ORANGE}{STRING1}
 STR_CONFIG_PATCHES_NEW_PATHFINDING_ALL                          :{LTBLUE}New global pathfinding (NPF, overrides NTP): {ORANGE}{STRING1}
+STR_CONFIG_PATCHES_AUTO_SEMAPHORES_PRE_DATE                     :{LTBLUE}Automatically build semaphores before: {ORANGE}{STRING1}
 STR_CONFIG_PATCHES_FREIGHT_TRAINS                               :{LTBLUE}Weight multiplier for freight to simulate heavy trains: {ORANGE}{STRING}
 
 STR_CONFIG_PATCHES_SMALL_AIRPORTS                               :{LTBLUE}Always allow small airports: {ORANGE}{STRING1}
Index: rail_cmd.c
===================================================================
--- rail_cmd.c	(revision 7559)
+++ rail_cmd.c	(working copy)
@@ -32,6 +32,7 @@
 #include "newgrf_callbacks.h"
 #include "newgrf_station.h"
 #include "train.h"
+#include "date.h"
 
 const byte _track_sloped_sprites[14] = {
 	14, 15, 22, 13,
@@ -654,6 +655,13 @@
 	sigvar = HASBIT(p1, 3) ? SIG_SEMAPHORE : SIG_ELECTRIC;
 	pre_signal = HASBIT(p1, 3);
 
+	/* If the current year is before the Light Signals introduction year
+	 * then inerchange Light and Semaphore signals.
+	 * Also do this if the option is set > 2010 ie Always build semaphores default. */
+	if ((_cur_year < _patches.semaphore_pre_year)
+	    || (_patches.semaphore_pre_year > 2010))
+		sigvar = (sigvar == SIG_SEMAPHORE) ? SIG_ELECTRIC : SIG_SEMAPHORE;
+
 	if (!ValParamTrackOrientation(track) || !IsTileType(tile, MP_RAILWAY) || !EnsureNoVehicle(tile))
 		return CMD_ERROR;
 
Index: settings.c
===================================================================
--- settings.c	(revision 7559)
+++ settings.c	(working copy)
@@ -1290,6 +1290,7 @@
 	SDT_BOOL(Patches, signal_side,                   N, 0,  true,        STR_CONFIG_PATCHES_SIGNALSIDE,          RedrawScreen),
 	SDT_BOOL(Patches, always_small_airport,          0, 0, false,        STR_CONFIG_PATCHES_SMALL_AIRPORTS,      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_pre_year,  SLE_UINT16,0,NC,  1975, MIN_YEAR, 2015,5, STR_CONFIG_PATCHES_AUTO_SEMAPHORES_PRE_DATE,NULL),
 
 	/***************************************************************************/
 	/* Vehicle section of the GUI-configure patches window */
Index: variables.h
===================================================================
--- variables.h	(revision 7559)
+++ variables.h	(working copy)
@@ -85,6 +85,7 @@
 	bool modified_catchment;            // different-size catchment areas
 	bool vehicle_speed;                 // show vehicle speed
 	bool build_on_slopes;               // allow building on slopes
+	uint16 semaphore_pre_year;          // automatic semaphores before set date
 	bool mammoth_trains;                // allow very long trains
 	bool join_stations;                 // allow joining of train stations
 	bool full_load_any;                 // new full load calculation, any cargo must be full
Index: settings_gui.c
===================================================================
--- settings_gui.c	(revision 7559)
+++ settings_gui.c	(working copy)
@@ -583,6 +583,7 @@
 	"always_small_airport",
 	"drag_signals_density",
 	"oil_refinery_limit",
+	"semaphore_pre_year",
 };
 
 static const char *_patches_stations[] = {