diff --git a/src/station_gui.cpp b/src/station_gui.cpp
index 2e336e86fa..32698ad3c9 100644
--- a/src/station_gui.cpp
+++ b/src/station_gui.cpp
@@ -730,7 +730,7 @@ public:
 	void OnGameTick() override
 	{
 		if (this->stations.NeedResort()) {
-			Debug(misc, 3, "Periodic rebuild station list company {}", this->window_number);
+			Debug(misc, 3, "Periodic rebuild station list company {}", static_cast<int>(this->window_number));
 			this->SetDirty();
 		}
 	}
diff --git a/src/window_func.h b/src/window_func.h
index 2bd314db99..530bad4ca1 100644
--- a/src/window_func.h
+++ b/src/window_func.h
@@ -12,7 +12,6 @@
 
 #include "window_type.h"
 #include "company_type.h"
-#include "core/convertible_through_base.hpp"
 #include "core/geometry_type.hpp"
 
 Window *FindWindowById(WindowClass cls, WindowNumber number);
@@ -20,11 +19,6 @@ Window *FindWindowByClass(WindowClass cls);
 Window *GetMainWindow();
 void ChangeWindowOwner(Owner old_owner, Owner new_owner);
 
-Window *FindWindowById(WindowClass cls, ConvertibleThroughBase auto number)
-{
-	return FindWindowById(cls, number.base());
-}
-
 void ResizeWindow(Window *w, int x, int y, bool clamp_to_screen = true, bool schedule_resize = true);
 int PositionMainToolbar(Window *w);
 int PositionStatusbar(Window *w);
@@ -43,11 +37,6 @@ void InputLoop();
 void InvalidateWindowData(WindowClass cls, WindowNumber number, int data = 0, bool gui_scope = false);
 void InvalidateWindowClassesData(WindowClass cls, int data = 0, bool gui_scope = false);
 
-void InvalidateWindowData(WindowClass cls, ConvertibleThroughBase auto number, int data = 0, bool gui_scope = false)
-{
-	InvalidateWindowData(cls, number.base(), data, gui_scope);
-}
-
 void CloseNonVitalWindows();
 void CloseAllNonVitalWindows();
 void DeleteAllMessages();
@@ -65,19 +54,9 @@ void SetWindowWidgetDirty(WindowClass cls, WindowNumber number, WidgetID widget_
 void SetWindowDirty(WindowClass cls, WindowNumber number);
 void SetWindowClassesDirty(WindowClass cls);
 
-void SetWindowDirty(WindowClass cls, ConvertibleThroughBase auto number)
-{
-	SetWindowDirty(cls, number.base());
-}
-
 void CloseWindowById(WindowClass cls, WindowNumber number, bool force = true, int data = 0);
 void CloseWindowByClass(WindowClass cls, int data = 0);
 
-void CloseWindowById(WindowClass cls, ConvertibleThroughBase auto number, bool force = true, int data = 0)
-{
-	CloseWindowById(cls, number.base(), force, data);
-}
-
 bool EditBoxInGlobalFocus();
 bool FocusedWindowIsConsole();
 Point GetCaretPosition();
diff --git a/src/window_gui.h b/src/window_gui.h
index f1c67bb7d3..a024a09029 100644
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -348,11 +348,6 @@ public:
 	void CreateNestedTree();
 	void FinishInitNested(WindowNumber window_number = 0);
 
-	void FinishInitNested(ConvertibleThroughBase auto number)
-	{
-		this->FinishInitNested(number.base());
-	}
-
 	/**
 	 * Set the timeout flag of the window and initiate the timer.
 	 */
@@ -995,11 +990,6 @@ public:
 Window *BringWindowToFrontById(WindowClass cls, WindowNumber number);
 Window *FindWindowFromPt(int x, int y);
 
-Window *BringWindowToFrontById(WindowClass cls, ConvertibleThroughBase auto number)
-{
-	return BringWindowToFrontById(cls, number.base());
-}
-
 /**
  * Open a new window.
  * @tparam Twindow %Window class to use if the window does not exist.
diff --git a/src/window_type.h b/src/window_type.h
index a71602e2a1..0c441689e4 100644
--- a/src/window_type.h
+++ b/src/window_type.h
@@ -10,6 +10,8 @@
 #ifndef WINDOW_TYPE_H
 #define WINDOW_TYPE_H
 
+#include "core/convertible_through_base.hpp"
+
 /**
  * Widget ID.
  * Even though the ID is signed, actual IDs must be non-negative.
@@ -736,8 +738,32 @@ enum GameOptionsInvalidationData : uint8_t {
 
 struct Window;
 
-/** Number to differentiate different windows of the same class */
-typedef int32_t WindowNumber;
+/**
+ * Number to differentiate different windows of the same class. This number generally
+ * implicitly passes some information, e.g. the TileIndex or Company associated with
+ * the window. To ease this use, the window number is lenient with what it accepts and
+ * broad with what it returns.
+ *
+ * Anything that converts into a number and ConvertibleThroughBase types will be accepted.
+ * When it's being used it returns int32_t or any other type when that's specifically
+ * requested, e.g. `VehicleType type = window_number` or `GetEngineListHeight(window_number)`
+ * in which the returned value will be a `VehicleType`.
+ */
+struct WindowNumber {
+private:
+	int32_t value = 0;
+public:
+	WindowNumber() = default;
+	WindowNumber(int32_t value) : value(value) {}
+	WindowNumber(ConvertibleThroughBase auto value) : value(value.base()) {}
+
+	/* Automatically convert to int32_t. */
+	operator int32_t() const { return value; }
+
+	/* Automatically convert to any other type that might be requested. */
+	template <typename T> requires (std::is_enum_v<T> || std::is_class_v<T>)
+	operator T() const { return static_cast<T>(value); };
+};
 
 /** State of handling an event. */
 enum EventState : uint8_t {