Thank you for the post. Hadn't known that a version of the XPT was nearly produced for Thailand but the deal fell through. I wonder if that's why they got the 158's.

 
43 years ago today (8th April 1982), a High Speed Train varient entered service in New South Wales ... still running to this day, though due to be retired in the next year, two, three

See https://en.wikipedia.org/wiki/New_South_Wales_XPT

At the time or writing, you can still travel on regular HST services in Australia, Mexico, Nigeria, Scotland and Cornwall. Their days are now numbered in Cornwall, Scotland and Australia - I don't know how long they're planned to run in Mexico and Nigeria, but clearly someone feels it's been worthwhile investing in their use there, and the Blue Pullman will be around, one might hope, for many years.  I note that the Hastings Diesel (not an HST) has now operated longer in preservation than in daily service, as has Waverley.  The same can be said for Brittania, and a number of other steam engines.  I look forward to a nostalgic trip on the Brighton Belle, though I suspect that there's a question there as to how much it's a preserved train and how much it's Pullman carriage bodies on following-generation under frames and also with more recent traction and control equipment.