London North Eastern Railway (LNER) announced its Azuma trains will enter service on 15 May between London and Leeds.
LNER said the Hitachi-built fleet is expected to enter service in Scotland in late summer, although industry sources told The Scotsman it may not be until November or December.
The trains are due to run as far as Edinburgh and Glasgow in electric mode, and using diesel power to Aberdeen and Inverness.
The fleet will cut journey times by accelerating faster than existing rolling stock.
They are due to reduce Edinburgh-London journeys by up to 40 minutes to four hours next year.
The trains were due to be launched in December, but this was delayed due to a series of problems, including their compatibility with signalling equipment, safety tests, staff training and new timetables.
LNER managing director David Horne described them as a “monumental
milestone for rail travel”.