--- a/src/vehicle.h	Wed Jun 13 11:45:14 2007 +0000
+++ b/src/vehicle.h	Wed Jun 13 12:05:56 2007 +0000
@@ -8,6 +8,7 @@
 #include "oldpool.h"
 #include "order.h"
 #include "rail.h"
+#include "road.h"
 
 /** The returned bits of VehicleEnterTile. */
 enum VehicleEnterTileStatus {
@@ -188,6 +189,11 @@
 	byte reverse_ctr;
 	struct RoadStop *slot;
 	byte slot_age;
+	EngineID first_engine;
+	byte cached_veh_length;
+
+	RoadType roadtype;
+	RoadTypes compatible_roadtypes;
 };
 
 struct VehicleSpecial {
@@ -395,6 +401,17 @@
 	 * Play the sound associated with leaving the station
 	 */
 	virtual void PlayLeaveStationSound() const {}
+
+	/**
+	 * Whether this is the primary vehicle in the chain.
+	 */
+	virtual bool IsPrimaryVehicle() const { return false; }
+
+	/**
+	 * Whether this vehicle understands the concept of a front engine, so
+	 * basically, if GetFirstVehicleInChain() can be called for it.
+	 */
+	virtual bool HasFront() const { return false; }
 };
 
 /**