From 8e9600991ab9fad17ff5740bac8aa659abbceb64 Mon Sep 17 00:00:00 2001
From: Jonathan G Rennison <j.g.rennison@gmail.com>
Date: Tue, 26 Mar 2024 17:46:56 +0000
Subject: [PATCH] Clear vehicle unit number on load for non-primary vehicles

---
 src/sl/vehicle_sl.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/sl/vehicle_sl.cpp b/src/sl/vehicle_sl.cpp
index 33b21242ad..3dcd4d6bcd 100644
--- a/src/sl/vehicle_sl.cpp
+++ b/src/sl/vehicle_sl.cpp
@@ -572,7 +572,11 @@ void AfterLoadVehicles(bool part_of_load)
 		}
 
 		if (part_of_load && v->unitnumber != 0) {
-			Company::Get(v->owner)->freeunits[v->type].UseID(v->unitnumber);
+			if (v->IsPrimaryVehicle()) {
+				Company::Get(v->owner)->freeunits[v->type].UseID(v->unitnumber);
+			} else {
+				v->unitnumber = 0;
+			}
 		}
 
 		v->UpdateDeltaXY();