Index: src/vehicle_base.h
===================================================================
--- src/vehicle_base.h	(revision 27655)
+++ src/vehicle_base.h	(working copy)
@@ -327,7 +327,7 @@
 	 */
 	inline uint GetOldAdvanceSpeed(uint speed)
 	{
-		return (this->direction & 1) ? speed : speed * 3 / 4;
+		return (this->direction & 1) ? speed : speed / 2;
 	}
 
 	/**
@@ -342,9 +342,9 @@
 	 * @param speed Direction-independent unscaled speed.
 	 * @return speed, scaled to match #GetAdvanceDistance().
 	 */
-	static inline uint GetAdvanceSpeed(uint speed)
+	inline uint GetAdvanceSpeed(uint speed)
 	{
-		return speed * 3 / 4;
+		return (this->type == VEH_TRAIN) ? (this->direction & 1) ? speed * 3 / 4 : speed / 2 : (speed * 3 / 4);
 	}
 
 	/**