First Great Western says it is going to get tough with the growing number of people who are using stolen or fake cards to buy tickets and services.
The train operator claims the fraud in ticket offices and refreshment areas is costing it £350,000 a year.
Rail staff are now being given training which is hoped will help them spot the stolen or forged cards.
The company says every pound cheated is money which denies honest passengers improvements in rail services.
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