Rail passengers 'given bad advice'
Undercover researchers asked rail staff for advice on the cheapest fare for 150 train journeys.
Which? said that 59% of station ticket clerks and 43% of operators on the National Rail Inquiries' line failed to advise passengers about cheaper options available.
In nine out of 10 cases, a passenger hoping to make two round trips from Oxford to Cardiff in a week was advised to buy two return tickets costing £200 each.
Which? also said that it had difficulty getting correct answers while searching for cheaper fare options on the nationalrail.co.uk website.
In addition, it surveyed 1,515 people who had travelled by train in the last 12 months. Only half felt confident that they knew how to get the best possible fare for their journey while 54% were satisfied overall with train services.
Which? chief executive Peter Vicary-Smith said: "Train operators seem blind to the fact that their ticketing systems are too complicated. If people who do this for a living can't find the cheapest fare, what hope do passengers have?"
But a spokesman for the Association of Train Operating Companies (Atoc) said: "This (report) is seriously misleading and misrepresentative. Asking 150 questions on unrealistic and obscure scenarios cannot come close to giving a representative view of the 1.3 billion journeys that are made every year by train.
"The researchers haven't actually asked for the cheapest ticket in all the scenarios and even where they have done, they have explicitly excluded the cheapest fares."