The Coastal Pacific is a long-distance passenger train operated by KiwiRail, running from Christchurch to Picton and return from Thursday to Sunday (it was a daily service at the time of filming). The Main North Line is 348 kilometres long, and the long section between Claverley and Wharanui runs alongside the Pacific Ocean. This coastal scenery is perhaps the most popular aspect of the journey, and you can connect with the Whale Watching experience at Kaikoura station.
On this occasion, the motive power was DXR 8007 (rebuilt from DX 5362 in 1993). I took a ride on the Coastal Pacific as an alternative to DA 1431's excursion to Arthur's Pass, which sold out before I got the chance to buy my ticket.