From caa0f6a044656be127f1820b6935a548057eb4a3 Mon Sep 17 00:00:00 2001
From: Jonathan G Rennison <j.g.rennison@gmail.com>
Date: Mon, 6 Jul 2020 17:21:24 +0100
Subject: [PATCH] TBTR: Relax assert restriction on new train in
 TransferCargoForTrain

---
 src/tbtr_template_vehicle_func.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tbtr_template_vehicle_func.cpp b/src/tbtr_template_vehicle_func.cpp
index c0c08a5f56..ec46805550 100644
--- a/src/tbtr_template_vehicle_func.cpp
+++ b/src/tbtr_template_vehicle_func.cpp
@@ -394,7 +394,7 @@ CommandCost TestBuyAllTemplateVehiclesInChain(TemplateVehicle *tv, TileIndex til
  */
 void TransferCargoForTrain(Train *old_veh, Train *new_head)
 {
-	assert(new_head->IsPrimaryVehicle());
+	assert(new_head->IsPrimaryVehicle() || new_head->IsFreeWagon());
 
 	CargoID _cargo_type = old_veh->cargo_type;
 	byte _cargo_subtype = old_veh->cargo_subtype;