We are planning a trip to Oz and want to incorporate the train journey from Adelaide to Perth across the Nullarbor. Do you know how long it takes and who sells it in the UK? Pam Delaney, Oxford

Sunday Times travel expert, Richard Green, responds: The great India Pacific rail journey from Sydney to Perth takes 65 hours, but the most popular part is the 38-hour stretch you are after, west from Adelaide.

The word "Nullarbor" is derived from the Latin for "no trees" and there's an especially desolate, swerve-free section of track there that lasts for a staggering 297 miles. It's the longest bit of straight railway line in the world ­ that's like catching a train from Southampton to Newcastle without once being driven round a bend.

Along the 16,00 miles of track, there's a short stop in the tiny settlement of Cook, with a population of four people, and another at the historic mining town of Kalgoorlie, from where there's the chance to grab a one-hour whistle stop tour.

The train departs Adelaide at 6:40pm on Sunday and Thursday and arrives Perth at 9:10am on Tuesday and Saturday. Austravel (0870 166 2070) sells the journey from £153pp one-way in a Red Kangaroo Daynighter Seat. This includes two nights in a reclining two-abreast lounge-style seat. Or you can upgrade to a cabin with the Gold Kangaroo Service from £578pp (based on two sharing a twin cabin), with en suite facilities and all meals.

You should consider The Ghan too. It runs north/south from Adelaide to Darwin, through Alice Springs. Named after the doughty Afghan camel trains that trekked down from the north, it passes right through the Red Centre, with swift stops at Alice Springs and Katherine Gorge. But The Ghan scores above the India Pacific in that you can break the journey by three days at Alice Springs, giving you time to visit Uluru and Kata Tjuta.

The trains covers the 1,851 miles from Adelaide to Darwin in 53 hours, with twice weekly departures; at 12:20pm on Sunday and Wednesday, arriving 5:30pm on Tuesday or 6:30pm on Friday. Fares are from £265pp one-way for a Red Kangaroo Daynighter Seat (as above), or from £759 for the Gold Kangaroo Service.

For general information, and to book, visit website of the Great Southern Railway. Or for bookings plus help planning your trip at either end of the train journey, contact Austravel (0870 166 2070), Trailfinders (0845 0585858), or Bridge and Wickers (020 7483 6555).

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