diff --git a/src/timetable_gui.cpp b/src/timetable_gui.cpp
--- a/src/timetable_gui.cpp
+++ b/src/timetable_gui.cpp
@@ -143,7 +143,7 @@ static void FillTimetableArrivalDepartur
  * @param w the window related to the setting of the date
  * @param date the actually chosen date
  */
-static void ChangeTimetableStartCallback(const Window *w, Date date, void *data)
+static void ChangeTimetableStartCallback(const Window *w, TimerGameCalendar::Date date, void *data)
 {
 	Command<CMD_SET_TIMETABLE_START>::Post(STR_ERROR_CAN_T_TIMETABLE_VEHICLE, (VehicleID)w->window_number, reinterpret_cast<std::uintptr_t>(data) != 0, date);
 }