JON Railton produced his best performance of the season to finish 21st in the fourth round of the Metzeler National Superstock 1000 championship at Cadwell Park. Despite struggling with wringing the full power from his bike, the 19-year-old from Grafham delivered an encouraging ride to make up 12 places in the afternoon's final race. Railton made the most of the tight, twisty and demanding Lincolnshire circuit, and finished 33rd in the field of over 50 riders. With the first 26 riders qualifying for the final automatically, Railton had to race in the shoot-out for one of the 10 remaining final grid slots. He had experienced trouble with his Aprilia, which suffered from lack of power in the straights, but after frantic work from his pit crew, Railton brought it home in seventh in the shoot-out to secure a final spot. From 33rd on the grid, Railton started positively and reeled in two places in the first lap, and continued to pick off riders as he progressed through the field. He made up a further 10 places to take 21st at the flag. Railton races next at the new Silverstone in June, and will hope to go even better after a test weekend at the circuit two weeks ago.