diff --git a/src/newgrf_engine.cpp b/src/newgrf_engine.cpp
index d052d16bb4..3bf9a93a45 100644
--- a/src/newgrf_engine.cpp
+++ b/src/newgrf_engine.cpp
@@ -1010,7 +1010,7 @@ static void DoTriggerVehicle(Vehicle *v, VehicleTrigger trigger, byte base_rando
 			 * i.e.), so we give them all the NEW_CARGO triggered
 			 * vehicle's portion of random bits. */
 			assert(first);
-			DoTriggerVehicle(GetFirstVehicleInChain(v), VEHICLE_TRIGGER_ANY_NEW_CARGO, new_random_bits, false);
+			DoTriggerVehicle((v->type == VEH_Train) ? GetFirstVehicleInChain(v) : v, VEHICLE_TRIGGER_ANY_NEW_CARGO, new_random_bits, false);
 			break;
 
 		case VEHICLE_TRIGGER_DEPOT:
diff --git a/src/vehicle.cpp b/src/vehicle.cpp
index 5197e6fc45..f76a49b965 100644
--- a/src/vehicle.cpp
+++ b/src/vehicle.cpp
@@ -515,6 +515,7 @@ Vehicle *GetFirstVehicleInChain(const Vehicle *v)
 	Vehicle* u;
 
 	assert(v != NULL);
+	assert(v->type == VEH_Train);
 
 	if (v->first != NULL) {
 		if (IsFrontEngine(v->first) || IsFreeWagon(v->first)) return v->first;