Fix incorrect way desc of bridge ramp

obj/bruecke.cc

@@ -183,6 +183,7 @@ void bruecke_t::finish_rd()
 			}
 		}
 	}
+	fix_ramp_desc_if_needed(gr);
 
 	player_t *player=get_owner();
 	// change maintenance
@@ -218,6 +219,38 @@ void bruecke_t::finish_rd()
 }
 
 
+// Old versions may set incorrect way desc to a bridge ramp.
+void bruecke_t::fix_ramp_desc_if_needed(const grund_t* gr) {
+	if(  desc->get_waytype()==powerline_wt  ) {
+		// no ramps for powerlines
+		return;
+	}
+	weg_t* weg = gr->get_weg_nr(0);
+	// check if the tile is a ramp
+	const slope_t::type slope = gr->get_grund_hang();
+	if(  slope==slope_t::flat  ) {
+		// This tile is a middle of the bridge.
+		return;
+	}
+	grund_t* adjacent_bridge_gr = NULL;
+	for(uint8 i=0; i<4; i++) {
+		grund_t* agr;
+		if(  !gr->get_neighbour(agr, desc->get_waytype(), (1<<i))  ||  agr->get_typ()!=grund_t::brueckenboden  ||  agr->get_grund_hang()!=slope_t::flat  ) {
+			// This is not a flat bridge tile
+			continue;
+		}
+		adjacent_bridge_gr = agr;
+		break;
+	}
+	const weg_t* adjacent_bridge_weg = adjacent_bridge_gr ? adjacent_bridge_gr->get_weg_nr(0) : NULL;
+	if(  !adjacent_bridge_weg  ) {
+		// adjacent bridge tile not found?
+		return;
+	}
+	weg->set_desc(adjacent_bridge_weg->get_desc());
+}
+
+
 // correct speed and maintenance
 void bruecke_t::cleanup( player_t *player2 )
 {

obj/bruecke.h

@@ -21,6 +21,8 @@ class bruecke_t : public obj_no_info_t
 	const bridge_desc_t *desc;
 	bridge_desc_t::img_t img;
 
+	void fix_ramp_desc_if_needed(const grund_t*);
+
 protected:
 	void rdwr(loadsave_t *file) OVERRIDE;