(svn r26152) -Revert/Fix (r26118) [FS#5822]: While the condition is non-sense, the 'true' case is required for articulated parts and the 'false' case is required for savegame compatibility.

src/roadveh_cmd.cpp

@@ -1416,6 +1416,18 @@ again:
 	if (new_dir != old_dir) {
 		v->direction = new_dir;
 		if (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) v->cur_speed -= v->cur_speed >> 2;
+
+		/* Delay the vehicle in curves by making it require one or two additional frames per curve.
+		 * A vehicle has to spend at least 9 frames on a tile, so the following articulated part can follow.
+		 * (The following part may only be one tile behind, and the front part is moved before the following ones.)
+		 * The short (inner) curve has 8 frames, this elongates it to 9 or 10.
+		 *
+		 * The difference between 9 and 10 is arbitrary, and completely bollocks (i.e. a bug).
+		 * Unifying this requires a complicated savegame conversion. */
+		if (old_dir != v->state) {
+			v->UpdateInclination(false, true);
+			return true;
+		}
 	}
 
 	/* If the vehicle is in a normal road stop and the frame equals the stop frame OR