diff --git a/src/command.cpp b/src/command.cpp
index 15d53e1f55..d88d3c1384 100644
--- a/src/command.cpp
+++ b/src/command.cpp
@@ -66,7 +66,7 @@ CommandProc CmdSellLandArea;
 CommandProc CmdBuildTunnel;
 
 CommandProc CmdBuildTrainDepot;
-CommandProc CmdBuildRailWaypoint;
+CommandProcEx CmdBuildRailWaypoint;
 CommandProc CmdRenameWaypoint;
 CommandProc CmdRemoveFromRailWaypoint;
 
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index 0321417ee5..7db316c791 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -50,8 +50,8 @@
 static RailType _cur_railtype;               ///< Rail type of the current build-rail toolbar.
 static bool _remove_button_clicked;          ///< Flag whether 'remove' toggle-button is currently enabled
 static DiagDirection _build_depot_direction; ///< Currently selected depot direction
-static byte _waypoint_count = 1;             ///< Number of waypoint types
-static byte _cur_waypoint_type;              ///< Currently selected waypoint type
+static uint _waypoint_count = 1;             ///< Number of waypoint types
+static uint _cur_waypoint_type;              ///< Currently selected waypoint type
 static bool _convert_signal_button;          ///< convert signal button in the signal GUI pressed
 static bool _trace_restrict_button;          ///< trace restrict button in the signal GUI pressed
 static bool _program_signal_button;          ///< program signal button in the signal GUI pressed
@@ -844,9 +844,11 @@ struct BuildRailToolbarWindow : Window {
 						} else {
 							TileArea ta(start_tile, end_tile);
 							uint32 p1 = _cur_railtype | (select_method == VPM_X_LIMITED ? AXIS_X : AXIS_Y) << 6 | ta.w << 8 | ta.h << 16 | _ctrl_pressed << 24;
-							uint32 p2 = STAT_CLASS_WAYP | _cur_waypoint_type << 8 | INVALID_STATION << 16;
+							uint32 p2 = STAT_CLASS_WAYP | INVALID_STATION << 16;
+							uint64 p3 = _cur_waypoint_type;
 
 							CommandContainer cmdcont = NewCommandContainerBasic(ta.tile, p1, p2, CMD_BUILD_RAIL_WAYPOINT | CMD_MSG(STR_ERROR_CAN_T_BUILD_TRAIN_WAYPOINT), CcPlaySound_CONSTRUCTION_RAIL);
+							cmdcont.p3 = p3;
 							ShowSelectWaypointIfNeeded(cmdcont, ta);
 						}
 					}
@@ -2291,7 +2293,7 @@ struct BuildRailWaypointWindow : PickerWindowBase {
 	{
 		switch (GB(widget, 0, 16)) {
 			case WID_BRW_WAYPOINT: {
-				byte type = GB(widget, 16, 16);
+				uint type = GB(widget, 16, 16);
 				const StationSpec *statspec = StationClass::Get(STAT_CLASS_WAYP)->GetSpec(type);
 				DrawWaypointSprite(r.left + 1 + ScaleGUITrad(31), r.bottom - ScaleGUITrad(31), type, _cur_railtype);
 
@@ -2306,7 +2308,7 @@ struct BuildRailWaypointWindow : PickerWindowBase {
 	{
 		switch (GB(widget, 0, 16)) {
 			case WID_BRW_WAYPOINT: {
-				byte type = GB(widget, 16, 16);
+				uint type = GB(widget, 16, 16);
 				this->GetWidget<NWidgetMatrix>(WID_BRW_WAYPOINT_MATRIX)->SetClicked(_cur_waypoint_type);
 
 				/* Check station availability callback */
diff --git a/src/script/api/script_rail.cpp b/src/script/api/script_rail.cpp
index 85b0195948..9a1a11e224 100644
--- a/src/script/api/script_rail.cpp
+++ b/src/script/api/script_rail.cpp
@@ -213,7 +213,7 @@
 	EnforcePrecondition(false, GetRailTracks(tile) == RAILTRACK_NE_SW || GetRailTracks(tile) == RAILTRACK_NW_SE);
 	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));
 
-	return ScriptObject::DoCommand(tile, GetCurrentRailType() | (GetRailTracks(tile) == RAILTRACK_NE_SW ? AXIS_X : AXIS_Y) << 6 | 1 << 8 | 1 << 16, STAT_CLASS_WAYP | INVALID_STATION << 16, CMD_BUILD_RAIL_WAYPOINT);
+	return ScriptObject::DoCommandEx(tile, GetCurrentRailType() | (GetRailTracks(tile) == RAILTRACK_NE_SW ? AXIS_X : AXIS_Y) << 6 | 1 << 8 | 1 << 16, STAT_CLASS_WAYP | INVALID_STATION << 16, 0, CMD_BUILD_RAIL_WAYPOINT);
 }
 
 /* static */ bool ScriptRail::RemoveRailWaypointTileRectangle(TileIndex tile, TileIndex tile2, bool keep_rail)
diff --git a/src/waypoint_cmd.cpp b/src/waypoint_cmd.cpp
index a259e41802..5fc6449f09 100644
--- a/src/waypoint_cmd.cpp
+++ b/src/waypoint_cmd.cpp
@@ -171,10 +171,13 @@ extern CommandCost IsRailStationBridgeAboveOk(TileIndex tile, const StationSpec
  * @param p2 various bitstuffed elements
  * - p2 = (bit  0- 7) - custom station class
  * - p2 = (bit  8-15) - custom station id
+ * - p2 = (bit 31-16) - station ID to join
+ * @param p3 various bitstuffed elements
+ * - p3 = (bit  0-31) - custom station id
  * @param text unused
  * @return the cost of this operation or an error
  */
-CommandCost CmdBuildRailWaypoint(TileIndex start_tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
+CommandCost CmdBuildRailWaypoint(TileIndex start_tile, DoCommandFlag flags, uint32 p1, uint32 p2, uint64 p3, const char *text, uint32 binary_length)
 {
 	/* Unpack parameters */
 	Axis axis      = Extract<Axis, 6, 1>(p1);
@@ -183,9 +186,10 @@ CommandCost CmdBuildRailWaypoint(TileIndex start_tile, DoCommandFlag flags, uint
 	bool adjacent  = HasBit(p1, 24);
 
 	StationClassID spec_class = Extract<StationClassID, 0, 8>(p2);
-	byte spec_index           = GB(p2, 8, 8);
 	StationID station_to_join = GB(p2, 16, 16);
 
+	uint spec_index           = GB(p3, 0, 32);
+
 	/* Check if the given station class is valid */
 	if (spec_class != STAT_CLASS_WAYP) return CMD_ERROR;
 	if (spec_index >= StationClass::Get(spec_class)->GetSpecCount()) return CMD_ERROR;