The Scottish 222 announcement gave dates, first ones in service by end of 2027, all in service by end of 2028
Realistically, as it says all will be overhauled, refurbished and get some upgrades, I would think first ones would be heading to works at least 6 months earlier (around April 2026), then a phased withdrawal of about 2 per month from summer 2027 to summer 2028. My guess, not an official timeline
ScotRail has announced plans to replace its high speed trains (HSTs) following a successful procurement process.A contract has been awarded to Beacon for the provision of twenty-two Class 222 trains, and to Alstom for the associated technical support, spares, and maintenance services. The trains...
www.scotrail.co.uk
I tend to believe the 2.5 year plan dates in Scotrail announcement rather more than the July 2019 (yes, over 7 years ago) East Midlands Railway announcement of dates for their 165 new carriages, that are about 4 years late (or about 230% of duration indicated)
Abellio UK, recently awarded the new eight-year EMR franchise by the Department for Transport, has awarded a £400 million contract to Hitachi Rail to build a pioneering new fleet of intercity trains.
www.eastmidlandsrailway.co.uk