diff --git a/src/train_cmd.cpp b/src/train_cmd.cpp
index 3f89d4f2e9..eead176b49 100644
--- a/src/train_cmd.cpp
+++ b/src/train_cmd.cpp
@@ -2531,7 +2531,7 @@ static bool HasLongReservePbsSignalOnTrackdir(Train* v, TileIndex tile, Trackdir
 			const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(tile, TrackdirToTrack(trackdir));
 			if (prog && prog->actions_used_flags & TRPAUF_LONG_RESERVE) {
 				TraceRestrictProgramResult out;
-				prog->Execute(v, TraceRestrictProgramInput(tile, trackdir, &VehiclePosTraceRestrictPreviousSignalCallback, nullptr), out);
+				prog->Execute(v, TraceRestrictProgramInput(tile, trackdir, &VehiclePosTraceRestrictPreviousSignalCallback, NULL), out);
 				if (out.flags & TRPRF_LONG_RESERVE) {
 					return true;
 				}