Added metro tram/train parameter switching

lang/english.lng

@@ -42,6 +42,7 @@ STR_TRAM_TRAINONLY               :Display all Metro units as Trains only (no tra
 STR_TRAM_TRAMONLY                :Display all Metro Units as Trams only (no London Underground trains etc, only as trams)
 STR_TRAM_BOTH                    :Display Trams and Trains as both Trams and Trains (all purchaseable as either)
 STR_TRAM_EXTRA                   :Display as both AND include some extra heavy rail units (Thameslink, Crossrail etc)
+STR_TRAM_SUPEREXTRA              :(Experimental) Include a slightly ridiculous number of extra units (London Overground, trains used for suburban routes)
 
 STR_PARAM_NAME_2CC              :Parameter not in use (yet)
 STR_PARAM_DESC_2CC              :Parameter reserved for future feature

src/grf.pnml

@@ -98,17 +98,19 @@ grf {
 				name: string(STR_PARAM_NAME_TRAM);
 				desc: string(STR_PARAM_DESC_TRAM);
 				min_value: 0;
-				max_value: 3;
+				max_value: 5;
 				def_value: 1;
 				names: {
 					0: string(STR_TRAM_DEFAULT);
 					1: string(STR_TRAM_TRAINONLY);
 					2: string(STR_TRAM_TRAMONLY);
 					3: string(STR_TRAM_BOTH);
+					4: string(STR_TRAM_EXTRA);
+					5: string(STR_TRAM_SUPEREXTRA);
 				};
 			}
 	}		
-	param 6 {
+	param 7 {
 			param_2cc{
 				name: string(STR_PARAM_NAME_2CC);
 				desc: string(STR_PARAM_DESC_2CC);

src/metroparam_switch.pnml

@@ -0,0 +1,35 @@
+// 0 : DEFAULT : (Default) Realistic Heavy/Light rail split (Trams and light rail as trams, heavy rail as trains)
+// 1 : TRAINONLY : Display all Metro units as Trains only (no trams)
+// 2 : TRAMONLY : Display all Metro Units as Trams only (no London Underground trains etc, only as trams)
+// 3 : BOTH : Display Trams and Trains as both Trams and Trains (all purchaseable as either)
+// 4 : EXTRA : Display as both AND include some extra heavy rail units (Thameslink, Crossrail etc)
+// 5 : SUPEREXTRA : (Experimental) Include a slightly ridiculous number of extra units (London Overground, trains used for suburban routes)
+
+if (param[6] < 5) {
+    // Disable "SUPEREXTRA" tram units at 5 or any setting below 5
+
+
+}
+
+if (param[6] < 4) {
+    // Disable "EXTRA" tram units at 4 or any setting below 4
+}
+
+// Do nothing when set to 3 specifically, "EXTRA" and "SUPEREXTRA" will already be removed above
+// and BOTH includes both tram and train versions so there's nothing to disable
+
+if (param[6] == 2) { // TRAM
+    // Disable train versions of all metro units
+}
+
+if (param[6] == 1) { // TRAIN
+    // Disable train versions of all metro units
+    disable_item(FEAT_TRAINS, 595); // London Underground 2024 stock tram
+}
+
+if (param[6] == 0) { // DEFAULT
+    // Disable tram versions of heavy rail units
+    disable_item(FEAT_ROADVEHS, 595); // London Underground 2024 stock tram
+
+    // Disable train versions of light rail versions
+}