 They are classified SW for cars with passenger saloon only, SWS with servery and SWG with luggage compartment and generator for power supply.The S stands for "Scenic Series" and "W" for "Wairarapa", to distinguish them from their Capital Connection counterparts, classified S.

On 11 May 2007, the first four cars entered service, with three more introduced on 18 June 2007 making up a 7-car consist.The remaining 11 cars entered service incrementally by the end of 2007.