Taking it to the Rails: WiMAX on Trains

By Jeff Goldman

April 02, 2008

UK-based Nomad Digital uses WiMAX to provide Internet access on trains--because, conveniently enough, both radio waves and railways go in straight lines.

UK-based Nomad Digital uses WiMAX to provide Internet access on trains--because, conveniently enough, both radio waves and railways go in straight lines.


Nigel Wallbridge and Graeme Lowdon founded the UK-based company Nomad Digital in 2002 to provide wireless connectivity to the public transportation sector. Nomad’s key differentiator, Wallbridge says, is its proprietary solution for enabling seamless hand-off between Wi-Fi, WiMAX, and just about any other technology.

“It’s all about taking low-cost technologies and making them mobile,” he says.

Last month, Nomad launched a pilot WiMax network in Stockholm, Sweden to provide Internet access on the Stockholm-to-Norrtalje route 676 commuter bus. Aside from that deployment, however, the company has generally targeted trains rather than buses, providing Wi-Fi access on Virgin TrainsWest Coast Main Line route (covering 528 miles of rail) and offering T-Mobile HotSpot access on the Heathrow Express train from Heathrow Airport to central London.

The response, Wallbridge says, has been extremely positive. Although the Heathrow Express ride is only 15 minutes long, he says the company is seeing average session times that are actually longer than 15 minutes.

“You’d think that in 15 minutes there wouldn’t be that much interest in getting onto a shuttle train ride like that, opening your laptop, and going through a sign-in process—but it’s immensely popular,” he says. “People want to have that connection.”

Wallbridge says Nomad is also working on supporting cell phone coverage.

“On lots of railways around the world, there isn’t sufficient voice coverage,” he says. “In that case, we put picocells on the train. The passenger’s cell phone speaks to the picocell in the carriage, and the carriage connects through our network to an IP network back to the network management center, and then is hauled back to the mobile network operators.”

And Nomad’s deployments aren’t just for the passengers.

“Without a doubt, this market has been kick-started by the hotspots business—but today, that’s a relatively small part of what we do,” Wallbridge says. “We’re providing communications between railways companies and their staff on the train. We’re providing remote CCTV monitoring of the train. We’re providing monitoring of on-board systems. We’re downloading information about where the train is, and whether all the doors and brakes and air conditioning systems are working.”

Nomad uses WiMAX for the majority of the backhaul, switching to a 3G network only in difficult areas—which are, generally speaking, curves.

“Think of what a railway line looks like: it’s straight lines connected by curves,” Wallbridge says. “We can do the straight lines very easily: we take a directional antenna and we point it straight down the railway line. But think of the curve—there may be just a few meters on that curve, and say there’s an S bend—you’d have to put in a base station just to cover that small part. So why bother?”

Instead, the company simply switches over to 3G for those few seconds, then hands off seamlessly back to the WiMAX connection for the next straight line. It’s those straight lines, Wallbridge says, that led him to rail deployments in the first place.

“I know it sounds ridiculous, but that was one of the early things I noticed: radio waves go in straight lines, and so do railways,” he says.

Nomad works with railroads in one of two ways—either by selling the system to the railroad or by acting as a service provider.

“Some railroads say, ‘We’d love these services, but we just can’t afford the capex to build the network,’” Wallbridge says. “And if the metrics of the railway are right, if there’s lots of ridership, if we think we can sell tons of services to tons of different people, then we’ll build the network at our cost, and operate it and sell services on it.”

While the company has largely used Redline WiMAX equipment in the past, Wallbridge says Nomad isn’t married to any single manufacturer—or even to any single technology.

“We’re pretty neutral on that,” he says. “Because we have this ability to switch between networks, we can add new technologies very, very cost-effectively.”

In future deployments, Wallbridge says the challenge will be to continue to meet an ever-increasing demand for bandwidth.

“Two or three years ago, we could manage with 2 Mbps to the train, but now we’re delivering 6 Mbps, and we’re looking ahead to delivering 20,” he says. “That’s just the nature of the beast.”

And looking forward, Wallbridge says it won’t only be about trains and buses—the company’s next target, he says, might just be cars.

“I don’t really know what the killer application is going to be, but it’s going to be there: people are going to want high-bandwidth connections to their vehicles,” he says. “Maybe they’re monitoring things on the vehicle, maybe navigation services, information services—all of that stuff is coming.”

Los Angeles-based writer Jeff Goldman is a frequent contributor to Wi-FiPlanet.

Originally published on .

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