diff --git a/src/timetable_cmd.cpp b/src/timetable_cmd.cpp
--- a/src/timetable_cmd.cpp
+++ b/src/timetable_cmd.cpp
@@ -67,7 +67,7 @@ CommandCost CmdChangeTimetable(TileIndex
 	VehicleID veh = GB(p1, 0, 16);
 
 	Vehicle *v = Vehicle::GetIfValid(veh);
-	if (v == NULL || !CheckOwnership(v->owner)) return CMD_ERROR;
+	if (v == NULL || !CheckOwnership(v->owner) || !v->IsPrimaryVehicle()) return CMD_ERROR;
 
 	VehicleOrderID order_number = GB(p1, 16, 8);
 	Order *order = v->GetOrder(order_number);
@@ -127,10 +127,11 @@ CommandCost CmdSetVehicleOnTime(TileInde
 	VehicleID veh = GB(p1, 0, 16);
 
 	Vehicle *v = Vehicle::GetIfValid(veh);
-	if (v == NULL || !CheckOwnership(v->owner)) return CMD_ERROR;
+	if (v == NULL || !CheckOwnership(v->owner) || !v->IsPrimaryVehicle()) return CMD_ERROR;
 
 	if (flags & DC_EXEC) {
 		v->lateness_counter = 0;
+		SetWindowDirty(WC_VEHICLE_TIMETABLE, v->index);
 	}
 
 	return CommandCost();
@@ -156,7 +157,7 @@ CommandCost CmdAutofillTimetable(TileInd
 	VehicleID veh = GB(p1, 0, 16);
 
 	Vehicle *v = Vehicle::GetIfValid(veh);
-	if (v == NULL || !CheckOwnership(v->owner)) return CMD_ERROR;
+	if (v == NULL || !CheckOwnership(v->owner) || !v->IsPrimaryVehicle()) return CMD_ERROR;
 
 	if (flags & DC_EXEC) {
 		if (HasBit(p2, 0)) {