Commuters in Tokyo are being greeted with the friendliest of welcomes. Some of the busiest

railway stations in the world have installed computerised 'smile scanners' to help employees

deliver a better service. From Tokyo

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Tokyo has some of the busiest train stations in the world. But now passengers can be assured of a friendly welcome from staff no matter how hard-pressed they are thanks to technology.

The computerised 'smile scanner' works by calculating the optimum curvature of the lips. Those with a low score are given words of advice, such as, 'you look too serious'. The idea is that workers maintain their computer-approved grins throughout the day.

Although the railway company says the smile scan system is not compulsory, all staff at the station have used it.

Taichi Takahashi from Keihin Express Railway:

I don't think we've had that much opportunity to stare at our faces that closely and for that long to check our facial expressions. The employees say the scan has helped them check their facial expressions, which helped them communicate more effectively with the customers.

So far the smile scanners have been installed at 15 train stations on the company's network, leaving grumpy workers with few places to hide.