GNER, which currently runs the InterCity East Coast rail, will hand over its IT infrastructure and software applications, including timetables, payrolls and train maintenance, to National Express, which will take over on 9 December.
"In the next five weeks, GNER will connect its Multiprotocol Label Switching voice and data network, which delivers IT services to 23 stations covering 600 miles between England and Scotland, to National Express's network," said Dave Edwards, GNER's head of procurement.
"GNER will also complete the roll out of a £2m electronic point of sale system on trains by November."
National Express Group said an IT team was already assessing GNER's systems.
"The handover will involve continuing some systems and re-licensing them, while migrating others on to our own IT systems. Obviously, some systems are common to running railways and this will be a straight handover," the firm said.
The Department for Transport awarded NXEC Trains, a subsidiary of National Express Group, the contract to operate services on the InterCity East Coast rail franchise in August. Although it did not audit the IT systems of bidders, the department said it was confident that the IT systems would run smoothly.
NXEC Trains is expected to deliver a range of new projects. These include a website that will highlight the cheapest available tickets on each train, smart cards to make buying tickets easier and a free Wi-Fi service extended to the whole train, not just first class.