It will refit CrossCountry’s existing Voyager trains, which were built by Alstom more than 20 years ago, with new seats, tables, carpets, lighting, and a passenger counting system.
Ben Goodwin, from Alstom, said this work at the Derby factory would bridge the gap between two big train building contracts.
He said: "We have been here almost 200 years, we want to be here for another 200 more, and by bringing in this kind of work to the site, it will really help us achieve that."
Alstom said design work on the renovation of 312 cars had started, with the physical refit set to commence at the Litchurch Lane site from next year until 2027.
The work, funded by Beacon Rail, will also include painting the exteriors in CrossCountry's new livery.
Mr Goodwin said the contract meant "more jobs for Derby, Derbyshire, [and] the East Midlands".
He added: "The work here will support around 100 Alstom roles, and we have a massive supply chain across the region and country that will benefit."
He said the trains served Derby, Nottingham and Burton-upon-Trent, so would benefit local jobs as well as passengers.
Earlier this year, Alstom had few orders and its future was uncertain.
However, Alstom recently signed a contract worth £370m to build 10 new nine-car Aventra trains for London's Elizabeth line.
The firm will also be building trains for HS2, along with Hitachi.
Mr Goodwin added: "But what this work we're announcing means, is it helps bridge those two big orders."
He said it would be looking for similar orders in the future.
"Bringing in services work where we maintain, refurbish and extend the life for rolling stock that is already in operation, it adds another feather to our cap," he said.
"We are future-proofing ourself for the long-term."
