New Delhi: Passengers on 25 trains can now choose their meals from a pre-loaded menu and pay through credit or debit cards without worrying about being overcharged or having to shell out the exact amount for their food, railway officials have said.

The facility, recently put into effect, will cover all zones in a phased manner, they said.

"The vendor will have a POS machine with pre-loaded software showing the passenger the menu as well as the prices. These cannot be fiddled with," a senior official said.

The prices will be fixed and passengers can pay for their meals with their cards, he added.

"This gives passengers three advantages - the food will be from an authorised vendor, they will get the meal at a fixed price and would not have to worry about giving the exact amount in cash," the official said.

The trains where such POS machines -- electronic devices used to process card payments -- have been provided include the Karnataka Express which runs between Bengaluru City and New Delhi, the Jammu Tawi-Kolkata Sealdah Express and Telengana Express running between Hyderabad and New Delhi.

The service will also be available on the Aravali Express which runs between Jaipur Junction and Mumbai.

The Railways at present has 76 POS machines and is now assessing on which trains they can be used, another official said.

The decision to introduce such hand-held devices was taken after the ministry received complaints from passengers about being over-charged for food, they said.

The Railways plans to provide each rake of a train with two POS machines to start with and then increase the numbers according to usage and the response from passengers.

The IRCTC is also deploying its officials on-board these trains to monitor the catering services. They are being provided with tablets to be used for collecting passenger feedback, it said.

The service providers managing the on-board services are also being trained at the IRCTC central kitchen at Noida for using POS machines, they said.