Commuters from Brighton to London's Victoria station can use free broadband on the train, thanks to a Wi-Fi-and-WiMax service. The Brighton Express is an apt place for a pioneering Wi-Fi service, given Brighton's role as a high-tech media-savvy remote suburb of London (and home of more than one Techworld stalwart), but T-Mobile hopes to make this the standard way to deliver Internet connectivity on the move.

Users get an 802.11b Wi-Fi service in the carriages. A pre-WiMax system from Redline connects from antennas on the carriage roofs to base stations by the side of the track (very much like the non-mobile system at the Science Museum). The service was integrated by Nomad Digital, a WiMax specialist, and will be offered free by T-Mobile for a trial period.

Goodbye to satellites
"This is the first broadband Wi-Fi service on trains in the UK," said Jay Saw, manager for T-Mobile Hotspot, the company's Wi-Fi service. Wi-Fi has previously been provided by satellite based systems, on GNER (Great North Eastern Railway) and Virgin Trains, but the T-Mobile service on Southern Railways' Brighton service gives a fast upload as well as download, he explained.

The service is not actually complete: 37 base stations are in operation, and around 60 will be needed to cover the whole line, explained Nigel Wallbridge, of Nomad Digital. In the meantime, users get continuous service, as the service migrates to GPRS - using three modems per train - when it loses the WiMax signal. When the base stations are all in place, it will be a 60 mile-long hotzone, said Saw.

The service is also limited by the uplinks from the base stations - most of which use commercial ADSL services at up to 2 Mbit/s. "This is the right bottleneck to have," said Wallbridge. "It is easy to upgrade those links, and there is plenty more capacity in the pre-WiMax links, which can go up to 32 Mbit/s."

So far, only one of Southern's Brighton Express trains has Wi-Fi, with another 14 scheduled to get the service as it is rolled out.

No need to wait for mobile WiMax
Surprisingly, the system does not need any of the refinements that are proposed for the mobile version of WiMax, 802.16e, which will not be available till next year. Instead, it uses a standard early implementation of 802.16d, according to Simon Wilder, sales director of Redline.

"Mobile WiMax is being designed with a view to ad hoc connections of mobile laptops," he explained. "In this system, there are a limited number of devices connecting by WiMax, with known IP addresses, and they are moving in a very predictable manner." Redline's equipment gives very good latency handling, he said.

Negotiating access to the cupboardThe companies would not talk about the commercial arrangements, although it costs around £30,000 and 30 man-hours to install equipment on a train, and £5000 to place a base station by the track. Most of the base stations so far have been sited on Southern's railway stations.

Both T-Mobile and Southern clearly see this as a test-bed. Both say they want to expand access on trains, but will wait to see how well the Brighton service is used.

T-Mobile approached Southern asking for a train to experiment with around 15 months ago, and Nomad has developed the service since then. As well as the Wi-Fi access points, The train carries a server, two WiMax routers, a GPS / GPRS box, and an uninterruptible power supply (UPS), all of which fits into a rack in one small cupboard.

One of the trickiest parts of the negotiation was getting access to that cupboard, said Wallbridge: "It used to be where the driver kept his sandwiches, and we had to reach an agreement."

Now the service is announced, usage has been climbing rapidly, with big peaks in the morning rush hour, says Saw. In June, T-Mobile will start charging at its normal rate for Wi-Fi hotspots - £5 per hour, or £13 for a one day pass (which can be used at other T-Mobile hotspots such as Starbucks).

Southern staff will probably be able to sell Wi-Fi vouchers, and leaflets about the service, but technical support will be by phone to T-Mobile.