The chief executive of National Rail Enquiries has said Indian call centre workers are more educated and do a better job than those in Britain.
Many companies have moved call centre operations overseas
Giving evidence to MPs on the transport select committee, Chris Scoggins said the service could be improved and made more accurate if outsourced to India.
He said the move could also save rail firms up to £25m over several years.
Union Amicus has asked to see evidence from the Association of Train Operating Companies (ATOC) to back up the claims.
Location, unless it is relevant to reliability, quality and value for money, has to be a matter for our suppliers
Association of Trade Operating Companies
Union officials believe if National Rail Enquiries is moved overseas it could threaten more than 1,000 jobs at call centres in Newcastle, Cardiff, Derby and Plymouth.
Mr Scoggins confirmed a pilot programme for rail enquiries was already under way in Bangalore, involving 10 call centre employees.
No final decisions have yet been made about the new contracts in the tendering process, he said.
As well as hearing from Atoc and union representations, the committee was also to hear from pressure group Rail Passenger Council, and from call-centre industry bodies.
Earlier this year Atoc, which awards the service contract, announced it would consider foreign bids.
David Fleming, Amicus national secretary, said: "What we have to establish is a culture of openness when companies decide to outsource.
"Atoc said last month they were only considering off-shoring when in actual fact they had already started."
Mr Fleming said he called rail enquiries on Monday and got a confused and unclear response to his query to travel from London to Burnley.
He said: "The operator admitted she was not in the UK but refused to say which country she was based.
"What have Atoc got to hide if they are instructing their staff to cover up the fact they are based thousands of miles away from the towns, cities and rail network they are supposed to service?"
Unions have been battling against a tide of call-centre jobs being switched overseas, complaining about the loss of work in the UK.
Companies have been warned that their image suffers when they open call centres in other countries.
But many firms have been outsourcing jobs because of huge savings on labour costs.
The current rail information contract is jointly run by First Information, Serco and BT.
Atoc said call answering contracts were up for competitive re-tendering at the end of he year, and the process would be carried out under EU procurement rules.
A spokesman said: "These rules require that we select suppliers on the basis of the most economically advantageous tender.
"Location, unless it is relevant to reliability, quality and value for money, has to be a matter for our suppliers."