From c0b051eb33821b5ea698149346921ae8b1122f59 Mon Sep 17 00:00:00 2001
From: smatz <smatz@openttd.org>
Date: Tue, 18 Jan 2011 20:40:36 +0000
Subject: [PATCH] (svn r21836) -Fix: when a train was reversed while inside a
 tunnel/bridge, it wouldn't have (re)set the GOINGUP/DOWN bits after leaving
 the tunnel/bridge

---
 src/train_cmd.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/train_cmd.cpp b/src/train_cmd.cpp
index a96d87b253..93d91f4c35 100644
--- a/src/train_cmd.cpp
+++ b/src/train_cmd.cpp
@@ -3146,6 +3146,11 @@ static void TrainController(Train *v, Vehicle *nomove)
 					TryReserveRailTrack(gp.new_tile, DiagDirToDiagTrack(GetTunnelBridgeDirection(gp.new_tile)));
 					CheckNextTrainTile(v);
 				}
+				/* Prevent v->UpdateInclination() being called with wrong parameters.
+				 * This could happen if the train was reversed inside the tunnel/bridge. */
+				if (gp.old_tile == gp.new_tile) {
+					gp.old_tile = GetOtherTunnelBridgeEnd(gp.old_tile);
+				}
 			} else {
 				v->x_pos = gp.x;
 				v->y_pos = gp.y;