--- a/command.c	Fri Jun 09 07:09:48 2006 +0000
+++ b/command.c	Fri Jun 09 07:45:26 2006 +0000
@@ -113,6 +113,7 @@
 DEF_COMMAND(CmdSellRoadVeh);
 DEF_COMMAND(CmdSendRoadVehToDepot);
 DEF_COMMAND(CmdTurnRoadVeh);
+DEF_COMMAND(CmdRefitRoadVeh);
 
 DEF_COMMAND(CmdPause);
 
@@ -245,7 +246,7 @@
 	{CmdSellRoadVeh,                         0}, /*  69 */
 	{CmdSendRoadVehToDepot,                  0}, /*  70 */
 	{CmdTurnRoadVeh,                         0}, /*  71 */
-	{NULL,                                   0}, /*  72 */
+	{CmdRefitRoadVeh,                        0}, /*  72 */
 
 	{CmdPause,                      CMD_SERVER}, /*  73 */
 

--- a/command.h	Fri Jun 09 07:09:48 2006 +0000
+++ b/command.h	Fri Jun 09 07:45:26 2006 +0000
@@ -91,6 +91,7 @@
 	CMD_SELL_ROAD_VEH = 69,
 	CMD_SEND_ROADVEH_TO_DEPOT = 70,
 	CMD_TURN_ROADVEH = 71,
+	CMD_REFIT_ROAD_VEH = 72,
 
 	CMD_PAUSE = 73,
 

--- a/lang/english.txt	Fri Jun 09 07:09:48 2006 +0000
+++ b/lang/english.txt	Fri Jun 09 07:45:26 2006 +0000
@@ -2591,6 +2591,11 @@
 STR_9038_GO_TO_ROADVEH_DEPOT                                    :Go to {TOWN} Road Vehicle Depot
 STR_SERVICE_AT_ROADVEH_DEPOT                                    :Service at {TOWN} Road Vehicle Depot
 
+STR_REFIT_ROAD_VEHICLE_TO_CARRY                                 :{BLACK}Refit road vehicle to carry a different cargo type
+STR_REFIT_ROAD_VEHICLE                                          :{BLACK}Refit road vehicle
+STR_REFIT_ROAD_VEHICLE_TO_CARRY_HIGHLIGHTED                     :{BLACK}Refit road vehicle to carry highlighted cargo type
+STR_REFIT_ROAD_VEHICLE_CAN_T                                    :{WHITE}Can't refit road vehicle...
+
 ##id 0x9800
 STR_9800_DOCK_CONSTRUCTION                                      :Dock construction
 STR_9801_DOCK_CONSTRUCTION                                      :{WHITE}Dock construction

--- a/roadveh_cmd.c	Fri Jun 09 07:09:48 2006 +0000
+++ b/roadveh_cmd.c	Fri Jun 09 07:45:26 2006 +0000
@@ -23,6 +23,7 @@
 #include "depot.h"
 #include "tunnel_map.h"
 #include "vehicle_gui.h"
+#include "newgrf_callbacks.h"
 #include "newgrf_engine.h"
 #include "yapf/yapf.h"
 
@@ -1721,3 +1722,87 @@
 		}
 	}
 }
+
+/** Refit a road vehicle to the specified cargo type
+ * @param tile unused
+ * @param p1 Vehicle ID of the vehicle to refit
+ * @param p2 Bitstuffed elements
+ * - p2 = (bit 0-7) - the new cargo type to refit to
+ * - p2 = (bit 8-15) - the new cargo subtype to refit to
+ */
+int32 CmdRefitRoadVeh(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	Vehicle *v;
+	int32 cost;
+	CargoID new_cid = GB(p2, 0, 8);
+	byte new_subtype = GB(p2, 8, 8);
+	uint16 capacity = CALLBACK_FAILED;
+
+	if (!IsVehicleIndex(p1)) return CMD_ERROR;
+
+	v = GetVehicle(p1);
+
+	if (v->type != VEH_Road || !CheckOwnership(v->owner)) return CMD_ERROR;
+	if (!IsRoadVehInDepotStopped(v)) return_cmd_error(STR_9013_MUST_BE_STOPPED_INSIDE);
+
+	if (new_cid > NUM_CARGO || !CanRefitTo(v->engine_type, new_cid)) return CMD_ERROR;
+
+	SET_EXPENSES_TYPE(EXPENSES_ROADVEH_RUN);
+
+	if (HASBIT(EngInfo(v->engine_type)->callbackmask, CBM_REFIT_CAPACITY)) {
+		/* Back up the cargo type */
+		CargoID temp_cid = v->cargo_type;
+		byte temp_subtype = v->cargo_subtype;
+		v->cargo_type = new_cid;
+		v->cargo_subtype = new_subtype;
+
+		/* Check the refit capacity callback */
+		capacity = GetVehicleCallback(CBID_VEHICLE_REFIT_CAPACITY, 0, 0, v->engine_type, v);
+
+		/* Restore the original cargo type */
+		v->cargo_type = temp_cid;
+		v->cargo_subtype = temp_subtype;
+	}
+
+	if (capacity == CALLBACK_FAILED) {
+		/* callback failed or not used, use default capacity */
+		const RoadVehicleInfo *rvi = RoadVehInfo(v->engine_type);
+
+		CargoID old_cid = rvi->cargo_type;
+		/* normally, the capacity depends on the cargo type, a vehicle can
+		 * carry twice as much mail/goods as normal cargo, and four times as
+		 * many passengers
+		 */
+		capacity = rvi->capacity;
+		switch (old_cid) {
+			case CT_PASSENGERS: break;
+			case CT_MAIL:
+			case CT_GOODS: capacity *= 2; break;
+			default:       capacity *= 4; break;
+		}
+		switch (new_cid) {
+			case CT_PASSENGERS: break;
+			case CT_MAIL:
+			case CT_GOODS: capacity /= 2; break;
+			default:       capacity /= 4; break;
+		}
+	}
+	_returned_refit_capacity = capacity;
+
+	cost = 0;
+	if (IS_HUMAN_PLAYER(v->owner) && new_cid != v->cargo_type) {
+		cost = _price.roadveh_base >> 7;
+	}
+
+	if (flags & DC_EXEC) {
+		v->cargo_cap = capacity;
+		v->cargo_count = (v->cargo_type == new_cid) ? min(capacity, v->cargo_count) : 0;
+		v->cargo_type = new_cid;
+		v->cargo_subtype = new_subtype;
+		InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
+		InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
+		RebuildVehicleLists();
+	}
+
+	return cost;
+}

--- a/roadveh_gui.c	Fri Jun 09 07:09:48 2006 +0000
+++ b/roadveh_gui.c	Fri Jun 09 07:45:26 2006 +0000
@@ -30,6 +30,7 @@
 {
 	const RoadVehicleInfo *rvi = RoadVehInfo(engine_number);
 	const Engine* e = GetEngine(engine_number);
+	bool refittable = (_engine_info[engine_number].refit_mask != 0);
 	YearMonthDay ymd;
 	ConvertDayToYMD(&ymd, e->intro_date);
 
@@ -47,7 +48,7 @@
 	/* Cargo type + capacity */
 	SetDParam(0, _cargoc.names_long[rvi->cargo_type]);
 	SetDParam(1, rvi->capacity);
-	SetDParam(2, STR_EMPTY);
+	SetDParam(2, refittable ? STR_9842_REFITTABLE : STR_EMPTY);
 	DrawString(x, y, STR_PURCHASE_INFO_CAPACITY, 0);
 	y += 10;
 
@@ -73,6 +74,87 @@
 	}
 }
 
+static void RoadVehRefitWndProc(Window *w, WindowEvent *e)
+{
+	switch (e->event) {
+		case WE_PAINT: {
+			const Vehicle *v = GetVehicle(w->window_number);
+
+			SetDParam(0, v->string_id);
+			SetDParam(1, v->unitnumber);
+			DrawWindowWidgets(w);
+
+			DrawString(1, 15, STR_983F_SELECT_CARGO_TYPE_TO_CARRY, 0);
+
+			WP(w,refit_d).cargo = DrawVehicleRefitWindow(v, WP(w,refit_d).sel);
+
+			if (WP(w,refit_d).cargo != CT_INVALID) {
+				int32 cost = DoCommand(v->tile, v->index, WP(w,refit_d).cargo, DC_QUERY_COST, CMD_REFIT_ROAD_VEH);
+				if (!CmdFailed(cost)) {
+					SetDParam(0, _cargoc.names_long[WP(w,refit_d).cargo]);
+					SetDParam(1, _returned_refit_capacity);
+					SetDParam(2, cost);
+					DrawString(1, 137, STR_9840_NEW_CAPACITY_COST_OF_REFIT, 0);
+				}
+			}
+
+			break;
+		}
+
+		case WE_CLICK:
+			switch (e->click.widget) {
+				case 2: { /* List box */
+					int y = e->click.pt.y - 25;
+					if (y >= 0) {
+						WP(w,refit_d).sel = y / 10;
+						SetWindowDirty(w);
+					}
+
+					break;
+				}
+
+				case 4: /* Refit button */
+					if (WP(w,refit_d).cargo != CT_INVALID) {
+						const Vehicle *v = GetVehicle(w->window_number);
+						if (DoCommandP(v->tile, v->index, WP(w,refit_d).cargo, NULL, CMD_REFIT_ROAD_VEH | CMD_MSG(STR_REFIT_ROAD_VEHICLE_CAN_T)))
+							DeleteWindow(w);
+					}
+					break;
+			}
+			break;
+	}
+}
+
+static const Widget _road_veh_refit_widgets[] = {
+{   WWT_CLOSEBOX, RESIZE_NONE, 14,  0,  10,   0,  13, STR_00C5,               STR_018B_CLOSE_WINDOW },
+{    WWT_CAPTION, RESIZE_NONE, 14, 11, 239,   0,  13, STR_983B_REFIT,         STR_018C_WINDOW_TITLE_DRAG_THIS },
+{     WWT_IMGBTN, RESIZE_NONE, 14,  0, 239,  14, 135, 0x0,                    STR_983D_SELECT_TYPE_OF_CARGO_FOR },
+{     WWT_IMGBTN, RESIZE_NONE, 14,  0, 239, 136, 157, 0x0,                    STR_NULL },
+{ WWT_PUSHTXTBTN, RESIZE_NONE, 14,  0, 239, 158, 169, STR_REFIT_ROAD_VEHICLE, STR_REFIT_ROAD_VEHICLE_TO_CARRY_HIGHLIGHTED },
+{    WIDGETS_END },
+};
+
+static const WindowDesc _road_veh_refit_desc = {
+	-1, -1, 240, 170,
+	WC_VEHICLE_REFIT, WC_VEHICLE_VIEW,
+	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_UNCLICK_BUTTONS,
+	_road_veh_refit_widgets,
+	RoadVehRefitWndProc,
+};
+
+static void ShowRoadVehRefitWindow(const Vehicle *v)
+{
+	Window *w;
+
+	DeleteWindowById(WC_VEHICLE_REFIT, v->index);
+
+	_alloc_wnd_parent_num = v->index;
+	w = AllocateWindowDesc(&_road_veh_refit_desc);
+	w->window_number = v->index;
+	w->caption_color = v->owner;
+	WP(w,refit_d).sel = -1;
+}
+
 static void RoadVehDetailsWndProc(Window *w, WindowEvent *e)
 {
 	switch (e->event) {
@@ -235,7 +317,10 @@
 		Vehicle *v = GetVehicle(w->window_number);
 		StringID str;
 
-		w->disabled_state = (v->owner != _local_player) ? (1<<8 | 1<<7) : 0;
+		w->disabled_state = (v->owner != _local_player) ? (1 << 8 | 1 << 7 | 1 << 12) : 0;
+
+		/* Disable refit button if vehicle not refittable */
+		if (_engine_info[v->engine_type].refit_mask == 0) SETBIT(w->disabled_state, 12);
 
 		/* draw widgets & caption */
 		SetDParam(0, v->string_id);
@@ -294,7 +379,7 @@
 		case 6: /* center main view */
 			ScrollMainWindowTo(v->x_pos, v->y_pos);
 			break;
-		case 7: /* goto hangar */
+		case 7: /* goto depot */
 			DoCommandP(v->tile, v->index, 0, NULL, CMD_SEND_ROADVEH_TO_DEPOT | CMD_MSG(STR_9018_CAN_T_SEND_VEHICLE_TO_DEPOT));
 			break;
 		case 8: /* turn around */
@@ -306,10 +391,12 @@
 		case 10: /* show details */
 			ShowRoadVehDetailsWindow(v);
 			break;
-		case 11: {
-			/* clone vehicle */
+		case 11: /* clone vehicle */
 			DoCommandP(v->tile, v->index, _ctrl_pressed ? 1 : 0, CcCloneRoadVeh, CMD_CLONE_VEHICLE | CMD_MSG(STR_9009_CAN_T_BUILD_ROAD_VEHICLE));
-			} break;
+			break;
+		case 12: /* Refit vehicle */
+			ShowRoadVehRefitWindow(v);
+			break;
 		}
 	} break;
 
@@ -321,6 +408,7 @@
 		break;
 
 	case WE_DESTROY:
+		DeleteWindowById(WC_VEHICLE_REFIT, w->window_number);
 		DeleteWindowById(WC_VEHICLE_ORDERS, w->window_number);
 		DeleteWindowById(WC_VEHICLE_DETAILS, w->window_number);
 		break;
@@ -330,7 +418,7 @@
 			Vehicle *v;
 			uint32 h;
 			v = GetVehicle(w->window_number);
-			h = IsRoadVehInDepotStopped(v) ? 1 << 7 : 1 << 11;
+			h = IsRoadVehInDepotStopped(v) ? (1 << 7) | (1 << 8) : (1 << 11) | (1 << 12);
 			if (h != w->hidden_state) {
 				w->hidden_state = h;
 				SetWindowDirty(w);
@@ -352,6 +440,7 @@
 { WWT_PUSHIMGBTN, RESIZE_LR,    14, 232, 249,  68,  85, 0x2B2,    STR_901D_SHOW_VEHICLE_S_ORDERS },
 { WWT_PUSHIMGBTN, RESIZE_LR,    14, 232, 249,  86, 103, 0x2B3,    STR_9021_SHOW_ROAD_VEHICLE_DETAILS },
 { WWT_PUSHIMGBTN, RESIZE_LR,    14, 232, 249,  32,  49, SPR_CLONE_ROADVEH,      STR_CLONE_ROAD_VEHICLE_INFO },
+{ WWT_PUSHIMGBTN, RESIZE_LR,    14, 232, 249,  50,  67, 0x2B4,    STR_REFIT_ROAD_VEHICLE_TO_CARRY },
 { WWT_PANEL,      RESIZE_LRB,   14, 232, 249, 104, 103, 0x0,      STR_NULL },
 { WWT_RESIZEBOX,  RESIZE_LRTB,  14, 238, 249, 104, 115, 0x0,      STR_NULL },
 { WIDGETS_END }

--- a/vehicle.c	Fri Jun 09 07:09:48 2006 +0000
+++ b/vehicle.c	Fri Jun 09 07:45:26 2006 +0000
@@ -59,7 +59,7 @@
 
 static const uint32 _veh_refit_proc_table[] = {
 	CMD_REFIT_RAIL_VEHICLE,
-	0,	// road vehicles can't be refitted
+	CMD_REFIT_ROAD_VEH,
 	CMD_REFIT_SHIP,
 	CMD_REFIT_AIRCRAFT,
 };
@@ -1658,14 +1658,12 @@
 		*w = new_v;	//we changed the vehicle, so MaybeReplaceVehicle needs to work on the new one. Now we tell it what the new one is
 
 		/* refit if needed */
-		if (new_v->type != VEH_Road) { // road vehicles can't be refitted
-			if (old_v->cargo_type != new_v->cargo_type && old_v->cargo_cap != 0 && new_v->cargo_cap != 0) {// some train engines do not have cargo capacity
-				// we add the refit cost to cost, so it's added to the cost animation
-				// it's not in the calculation of having enough money to actually do the replace since it's rather hard to do by design, but since
-				// we pay for it, it's nice to make the cost animation include it
-				int32 temp_cost = DoCommand(0, new_v->index, old_v->cargo_type, DC_EXEC, CMD_REFIT_VEH(new_v->type));
-				if (!CmdFailed(temp_cost)) cost += temp_cost;
-			}
+		if (old_v->cargo_type != new_v->cargo_type && old_v->cargo_cap != 0 && new_v->cargo_cap != 0) {// some train engines do not have cargo capacity
+			// we add the refit cost to cost, so it's added to the cost animation
+			// it's not in the calculation of having enough money to actually do the replace since it's rather hard to do by design, but since
+			// we pay for it, it's nice to make the cost animation include it
+			int32 temp_cost = DoCommand(0, new_v->index, old_v->cargo_type, DC_EXEC, CMD_REFIT_VEH(new_v->type));
+			if (!CmdFailed(temp_cost)) cost += temp_cost;
 		}
 		if (new_v->type == VEH_Train && HASBIT(old_v->u.rail.flags, VRF_REVERSE_DIRECTION) && !IsMultiheaded(new_v) && !(new_v->next != NULL && IsArticulatedPart(new_v->next))) {
 			// we are autorenewing to a single engine, so we will turn it as the old one was turned as well