3 files changed, 52 insertions, 16 deletions

diff --git a/src/rail.cpp b/src/rail.cpp
index c97dfb53c..f2870c1eb 100644
--- a/src/rail.cpp
+++ b/src/rail.cpp
@@ -262,13 +262,14 @@ RailTypes AddDateIntroducedRailTypes(RailTypes current, Date date)
 /**
  * Get the rail types the given company can build.
  * @param company the company to get the rail types for.
+ * @param introduces If true, include rail types introduced by other rail types
  * @return the rail types.
  */
-RailTypes GetCompanyRailtypes(CompanyID company)
+RailTypes GetCompanyRailtypes(CompanyID company, bool introduces)
 {
 	RailTypes rts = RAILTYPES_NONE;
 
-	Engine *e;
+	const Engine *e;
 	FOR_ALL_ENGINES_OF_TYPE(e, VEH_TRAIN) {
 		const EngineInfo *ei = &e->info;
 
@@ -278,12 +279,46 @@ RailTypes GetCompanyRailtypes(CompanyID company)
 
 			if (rvi->railveh_type != RAILVEH_WAGON) {
 				assert(rvi->railtype < RAILTYPE_END);
+				if (introduces) {
+					rts |= GetRailTypeInfo(rvi->railtype)->introduces_railtypes;
+				} else {
+					SetBit(rts, rvi->railtype);
+				}
+			}
+		}
+	}
+
+	if (introduces) return AddDateIntroducedRailTypes(rts, _date);
+	return rts;
+}
+
+/**
+ * Get list of rail types, regardless of company availability.
+ * @param introduces If true, include rail types introduced by other rail types
+ * @return the rail types.
+ */
+RailTypes GetRailTypes(bool introduces)
+{
+	RailTypes rts = RAILTYPES_NONE;
+
+	const Engine *e;
+	FOR_ALL_ENGINES_OF_TYPE(e, VEH_TRAIN) {
+		const EngineInfo *ei = &e->info;
+		if (!HasBit(ei->climates, _settings_game.game_creation.landscape)) continue;
+
+		const RailVehicleInfo *rvi = &e->u.rail;
+		if (rvi->railveh_type != RAILVEH_WAGON) {
+			assert(rvi->railtype < RAILTYPE_END);
+			if (introduces) {
 				rts |= GetRailTypeInfo(rvi->railtype)->introduces_railtypes;
+			} else {
+				SetBit(rts, rvi->railtype);
 			}
 		}
 	}
 
-	return AddDateIntroducedRailTypes(rts, _date);
+	if (introduces) return AddDateIntroducedRailTypes(rts, MAX_DAY);
+	return rts;
 }
 
 /**
diff --git a/src/rail.h b/src/rail.h
index b08f0650a..004593ce7 100644
--- a/src/rail.h
+++ b/src/rail.h
@@ -455,7 +455,8 @@ bool ValParamRailtype(const RailType rail);
 RailTypes AddDateIntroducedRailTypes(RailTypes current, Date date);
 
 RailType GetBestRailtype(const CompanyID company);
-RailTypes GetCompanyRailtypes(const CompanyID c);
+RailTypes GetCompanyRailtypes(CompanyID company, bool introduces = true);
+RailTypes GetRailTypes(bool introduces);
 
 RailType GetRailTypeByLabel(RailTypeLabel label, bool allow_alternate_labels = true);
 
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index 827f24456..176e8e6ef 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -1989,20 +1989,20 @@ void InitializeRailGUI()
  */
 DropDownList *GetRailTypeDropDownList(bool for_replacement, bool all_option)
 {
-	RailTypes used_railtypes = RAILTYPES_NONE;
+	RailTypes used_railtypes;
+	RailTypes avail_railtypes;
 
-	/* Find the used railtypes. */
-	Engine *e;
-	FOR_ALL_ENGINES_OF_TYPE(e, VEH_TRAIN) {
-		if (!HasBit(e->info.climates, _settings_game.game_creation.landscape)) continue;
+	const Company *c = Company::Get(_local_company);
 
-		used_railtypes |= GetRailTypeInfo(e->u.rail.railtype)->introduces_railtypes;
+	/* Find the used railtypes. */
+	if (for_replacement) {
+		avail_railtypes = GetCompanyRailtypes(c->index, false);
+		used_railtypes  = GetRailTypes(false);
+	} else {
+		avail_railtypes = c->avail_railtypes;
+		used_railtypes  = GetRailTypes(true);
 	}
 
-	/* Get the date introduced railtypes as well. */
-	used_railtypes = AddDateIntroducedRailTypes(used_railtypes, MAX_DAY);
-
-	const Company *c = Company::Get(_local_company);
 	DropDownList *list = new DropDownList();
 
 	if (all_option) {
@@ -2030,9 +2030,9 @@ DropDownList *GetRailTypeDropDownList(bool for_replacement, bool all_option)
 		StringID str = for_replacement ? rti->strings.replace_text : (rti->max_speed > 0 ? STR_TOOLBAR_RAILTYPE_VELOCITY : STR_JUST_STRING);
 		DropDownListParamStringItem *item;
 		if (for_replacement) {
-			item = new DropDownListParamStringItem(str, rt, !HasBit(c->avail_railtypes, rt));
+			item = new DropDownListParamStringItem(str, rt, !HasBit(avail_railtypes, rt));
 		} else {
-			DropDownListIconItem *iconitem = new DropDownListIconItem(rti->gui_sprites.build_x_rail, PAL_NONE, str, rt, !HasBit(c->avail_railtypes, rt));
+			DropDownListIconItem *iconitem = new DropDownListIconItem(rti->gui_sprites.build_x_rail, PAL_NONE, str, rt, !HasBit(avail_railtypes, rt));
 			iconitem->SetDimension(d);
 			item = iconitem;
 		}