diff --git a/src/order_cmd.cpp b/src/order_cmd.cpp
index ea040dc7da..9ee7841a2e 100644
--- a/src/order_cmd.cpp
+++ b/src/order_cmd.cpp
@@ -2122,7 +2122,10 @@ CommandCost CmdModifyOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 						break;
 
 					case OCV_TIMETABLE:
-						if (!old_var_was_tt) order->GetXDataRef() = 0;
+						if (!old_var_was_tt) {
+							order->SetConditionValue(0);
+							order->GetXDataRef() = 0;
+						}
 						if (occ == OCC_IS_TRUE || occ == OCC_IS_FALSE || occ == OCC_EQUALS || occ == OCC_NOT_EQUALS) order->SetConditionComparator(OCC_LESS_THAN);
 						break;