The rail minister has said the government is concerned that Christmas train services could be disrupted due to staff shortages.
Lord Handy said the Department for Transport would “keep a close eye on staff” during the holidays.
The disruptions could also be exacerbated by fresh industrial action. Avanti West Coast train managers are voting to strike for three days during the festival.
Recruitment has proven difficult across the rail industry, leaving train operating companies dependent on staff volunteering to work extra paid shifts, particularly during peak periods.
A Department for Transport official told MPs that the railway system generally “relies heavily on overtime work” for train crews, particularly around Christmas.
Many train drivers and other staff members do not have Sunday working included in their contracts, with some operators offering extra paid shifts to ensure services can run.
On Tuesday, the Rail, Maritime and Transport (RMT) union said walkouts were planned for Avanti services on December 22, 23 and 29, after it demanded “rest day work arrangements” from the train company. The proposals were rejected.
Train managers normally work 41 hours a week but may be asked to work on holidays due to staff shortages.
However, the RMT has described the current arrangements as “unacceptable”, with around 300 train managers expected to walk out.
Avanti West Coast said customers would face “significant disruption” during “our busiest and most important” time of year.
The announcement came weeks after RMT members working for several other rail companies accepted pay rises of 4.75% for the last financial year and 4.5% for 2024-25.
However, those working for the North recently rejected it. Four months’ salary offered by the firm to conductors working on Sundays.
As a result, passengers may experience disruptions to its services in December, the company said.
Lord Handy told MPs on the Commons Transport Committee that there were concerns that the closure of some sections of the railway over Christmas could put more pressure on others.
The UK’s rail network closes completely on Christmas Day each year, with limited service on Boxing Day.
Many routes will remain closed for longer periods during the festival as Network Rail, which owns and maintains the railway, carry out engineering work.
Lord Handy, who chaired Network Rail from 2015 until he was brought into Labor government, said: “Christmas is a good time to do major engineering work, as demand has been low for several days.”
Network Rail has previously said that passenger numbers at major stations typically fall by 50 to 60 per cent during the seven days between Christmas Day and New Year compared to a week in November or early December.