diff --git a/gfx.c b/gfx.c
--- a/gfx.c
+++ b/gfx.c
@@ -430,7 +430,7 @@ static uint32 FormatStringLinebreaks(cha
 	}
 }
 
-void DrawStringMultiCenter(int x, int y, uint16 str, int maxw)
+void DrawStringMultiCenter(int x, int y, StringID str, int maxw)
 {
 	char buffer[512];
 	uint32 tmp;
@@ -476,7 +476,7 @@ void DrawStringMultiCenter(int x, int y,
 	}
 }
 
-void DrawStringMultiLine(int x, int y, uint16 str, int maxw)
+void DrawStringMultiLine(int x, int y, StringID str, int maxw)
 {
 	char buffer[512];
 	uint32 tmp;
diff --git a/gfx.h b/gfx.h
--- a/gfx.h
+++ b/gfx.h
@@ -68,8 +68,8 @@ uint16 GetDrawStringPlayerColor(PlayerID
 
 int GetStringWidth(const char *str);
 void LoadStringWidthTable(void);
-void DrawStringMultiCenter(int x, int y, uint16 str, int maxw);
-void DrawStringMultiLine(int x, int y, uint16 str, int maxw);
+void DrawStringMultiCenter(int x, int y, StringID str, int maxw);
+void DrawStringMultiLine(int x, int y, StringID str, int maxw);
 void DrawDirtyBlocks(void);
 void SetDirtyBlocks(int left, int top, int right, int bottom);
 void MarkWholeScreenDirty(void);
diff --git a/openttd.c b/openttd.c
--- a/openttd.c
+++ b/openttd.c
@@ -789,9 +789,9 @@ void SwitchMode(int new_mode)
 	}
 
 	case SM_LOAD_SCENARIO: { /* Load scenario from scenario editor */
-		int i;
+		if (SafeSaveOrLoad(_file_to_saveload.name, _file_to_saveload.mode, GM_EDITOR)) {
+			PlayerID i;
 
-		if (SafeSaveOrLoad(_file_to_saveload.name, _file_to_saveload.mode, GM_EDITOR)) {
 			_opt_ptr = &_opt;
 
 			_local_player = OWNER_NONE;
@@ -1283,8 +1283,9 @@ bool AfterLoadGame(uint version)
 	}
 
 	if (version < 0x1000) {
-		int i;
 		FOR_ALL_PLAYERS(p) {
+			EngineID i;
+
 			for (i = 0; i < TOTAL_NUM_ENGINES; i++) {
 				p->engine_replacement[i] = INVALID_ENGINE;
 			}
diff --git a/players.c b/players.c
--- a/players.c
+++ b/players.c
@@ -619,7 +619,7 @@ void DeletePlayerWindows(PlayerID pi)
 byte GetPlayerRailtypes(PlayerID p)
 {
 	byte rt = 0;
-	uint i;
+	EngineID i;
 
 	for (i = 0; i != TOTAL_NUM_ENGINES; i++) {
 		const Engine* e = GetEngine(i);
diff --git a/train_cmd.c b/train_cmd.c
--- a/train_cmd.c
+++ b/train_cmd.c
@@ -1958,7 +1958,8 @@ static bool CheckTrainStayInDepot(Vehicl
 			return false;
 
 	if (v->u.rail.force_proceed == 0) {
-		byte trackdir = GetVehicleTrackdir(v);
+		Trackdir trackdir = GetVehicleTrackdir(v);
+
 		if (++v->load_unload_time_rem < 37) {
 			InvalidateWindowClasses(WC_TRAINS_LIST);
 			return true;
diff --git a/vehicle.h b/vehicle.h
--- a/vehicle.h
+++ b/vehicle.h
@@ -240,7 +240,7 @@ struct Vehicle {
 	int32 top_coord;
 	int32 right_coord;
 	int32 bottom_coord;
-	uint16 next_hash;
+	VehicleID next_hash;
 
 	// Related to age and service time
 	uint16 age;				// Age in days
diff --git a/window.h b/window.h
--- a/window.h
+++ b/window.h
@@ -56,7 +56,7 @@ typedef struct Widget {
 	byte color;
 	uint16 left, right, top, bottom;
 	uint16 unkA;
-	uint16 tooltips;
+	StringID tooltips;
 } Widget;
 
 enum FrameFlags {