The express train service from Central London to Heathrow Airport has installed an e-ticketing system that sends a bar code to a passenger's mobile phone.

The service is intended to make it more convenient and faster for customers to book a seat. Travelers can purchase a ticket through the Heathrow Express Web site, and a bar code is sent to the mobile phone, which is scanned by the conductor. People can also opt to print out the ticket.

It's the first installation of AVANTIXMetro, a mobile ticketing system from Atos Origin. Passengers will still be able to buy tickets on the train or at the kiosks at Paddington Station, where the Heathrow Express starts its 15-minute journey to the western London airport.

Conductors will use a Casio IT-3000 handheld data terminal to scan mobile devices. The terminal has an integrated thermal printer and is equipped with Bluetooth and infrared connectivity, as well as a PCMCIA slot for GPRS (General Packet Radio Service) or Wi-Fi connectivity, Atos Origin said.

To receive an e-ticket on their phone, customers will be required to register themselves and their phone at the Heathrow Express Web site. Once a ticket is purchased, a person will receive a Web link by SMS (Short Message Service), which will show the bar code.

Riders will get a modest discount for using e-ticketing: £14.50 (US$28.61) for a one-way express class fare. Tickets purchased at the station are £15.50, while those bought on the train are a steeper £17.50.

E-ticketing is becoming more prevalent, with airlines moving to the systems to save on costs and entertainment companies issuing mobile phone concert tickets to save on delivery fees.