Rail ticketing will be made simpler and easier to understand, Transport Secretary Ruth Kelly has promised.
Which? magazine called for better training of rail staff
Her pledge follows a survey by Which? suggesting about only half of people who make enquiries get the "best deal".
The consumer watchdog's study asked the same 25 questions of the National Rail Enquiries phone line and ticket office staff at stations.
National Rail Enquiries chief executive Chris Scoggins said the sample size of questions was "astonishingly small".
Ms Kelly said at the Labour Party conference that she would make sure people "can be confident they're getting the right ticket at the right price".
In the Which? survey, a single journey from London to Grantham in Lincolnshire was quoted as £44.50 when the passenger could have travelled for only £20 on a train leaving 10 minutes earlier.
In another example, a passenger making a return journey between Swindon and Penzance twice in the same week could buy a Freedom of the South West rover ticket for £70, but both the enquiry line staff and station staff quoted £67 per journey - nearly double the cheapest price.
Which? called for staff training to be improved, while rail customer watchdog Passenger Focus said fare structures needed to be simplified to help passengers get the best deals.
Which? said the National Rail Enquiries website did supply it with the best value fares.
Mr Scoggins told BBC News: "The problem with this survey is that it is just a sample of 25, an astonishingly small sample size, as has been the case of Which? reports in previous years.
"We employ two independent expert external companies who, between them, measure 18,000 of our calls a year and on that scale of sample we actually get 97.2% correct."
The Association of Train Operating Companies (Atoc) also said the survey sample was too small to be representative.
It said the amount of times National Rail Enquiries gave correct information was 96.1% from October 2006 to March 2007, and 97.2% for April to August 2007.
Atoc also said the level of complaints about the service had fallen yearly, with the current rate at one out of every 9,000 calls.
Independent market research mystery shopper tests had shown that booking office staff sold the correct ticket 99.1% of the time, the organisation added.