Series 9 (2005) and 10 (2006) saw the expansion of the supporting cast with new and old characters. From Series 9 the narrator would call out the episodes' names and from Series 11 the theme song was sung starting with the sound of a train whistle. Series 10 aired with twenty-eight episodes rather than the twenty-six of previous years. The eleventh series (2007) was filmed in high definition format. Twenty episodes aired in the original broadcast, while six were released directed to DVD as Engines and Escapades. Jocelyn Stevenson had stepped down as executive producer after Series 10, with Christopher Skala taking her place as executive producer for Series 11. Sharon Miller became the script editor from Series 9 to 11.