Airports and other public transit hubs are spreading out, while life is speeding up, creating demand for moving walkways that run faster than today’s three-kilometer-per-hour models. But at least half a dozen attempts to rise to the challenge have stumbled in recent decades.

The latest attempt, the trottoir roulant rapide (“fast-moving sidewalk”), which shuttles commuters across the sprawling Montparnasse Metro station in Paris, has endured the test of time, if ungracefully.

Since its launch in 2002, the “Gateway,” as it’s known, has acquired a reputation for tripping passengers and breaking down – a reputation some of its patrons believe is no longer warranted, as bugs in the system have been worked out.

What is not in dispute, however, is that the walkway’s speed has been in freefall. Designed for a top speed of 12 kilometers per hour, the Gateway was nicknamed “TRGV,” (trottoir roulant grande vitesse), after France’s TGV intercity trains, which average 300 kph. The nickname endures – with more than a tinge of irony, since its overall speed has plummeted to a pokey 4.5 kph – roughly the stride of a vigorous commuter.

Constructions Industrielles de la Méditerranée (CNIM), the Paris-based industrial conglomerate behind the Gateway, pooh-poohs the criticisms and argues that more than three years of operation proves the Gateway is the first high-speed walkway ready for international markets.

“Already 13 million passengers have used the gateway. It’s clearly some success,” says CNIM business development manager Eric Pourquey. Despite the hiccups in speed, the company claims there is some demand for the high-speed walkway. What’s more, merchants near the Gateway in Montparnasse have confirmed a series of recent visits by officials from Toronto’s airport authority.

That would have been unimaginable back in July 2002, when Gateway launched amid great fanfare, but quickly tumbled into embarrassment. Jean-Paul Huchon, president of the Paris regional government and a financial supporter, gushed that the Gateway would “teleport” commuters from one line to the next at 11-kph – like “capitaines Kirk” beaming down from the Enterprise. Transports en Ile-de-France (RATP), the authority that runs the Paris metro, calculated that commuters riding the Gateway twice a day would save 10 hours per year.

Just days later, however, unseasoned riders were getting tossed around on the walkway, some unlucky ones even breaking bones after harsh falls.

The calamitous launch was less an engineering problem, though, than a failure by humans to behave as the engineers had expected. Since an 11-kph walkway is too difficult to step on and step off, Gateway riders are gradually accelerated via a 10-meter-long carpet of steel wheels resembling thick quarters. The first rollers are going about 2.2 kph, and subsequent rollers increase the speed until the 11-kph velocity is reached. As riders approach the end of the ramp, deceleration occurs in the same way.

But the system only works if passengers step on the slow-moving walkway and grab the handrails, letting the walkway take them for a ride. Instead, impatient Gateway riders would step over the transitions, planting their feet on a fast moving walkway, and causing them to lose their balance.

The RATP and CNIM shut the Gateway down within days of launch and relaunched three months later, with new video and audio warnings instructing passengers on proper behavior. As Lucien Le Gousse, the RATP maintenance engineer for the Gateway, says, the goal was to “make the users understand, in some fractions of a second, that they were not on the rolling walkways they had taken for 30 years.” Around this time, says Le Gousse, RATP also slowed the walkway’s top speed to 9 kph.

The result was a much safer system. In 2004, RATP demonstrated that the Gateway injury rate was comparable with existing walkways and escalators (about eight accidents per 10 million trips), earning the mechanism a permanent operating permit. And it’s probably even safer today, since the fastest it runs now is about 6 kph – and then only during the morning and evening rush hours. As a result, merchants who work nearby say accidents are few. “The people who fall – it’s their own fault,” claims Messa, a florist stationed at the south end.

Reliability, however, is another issue. RATP’s Le Gousse insists that he is satisfied with the 87 percent availability the Gateway achieved last year. The local merchants, however, describe a walkway that’s forever breaking down – sometimes as often as twice a day. Making the breakdowns even more maddening are the reasons, such as a pebble stuck in the complex roller system, grinding the walkway to halt. “It’s always out of service,” says Ahmed Abderemane, who sells magazines and snacks five days a week at the Gateway’s northern end.

Is it worth the trouble? Abderemane doesn’t think so. He says that at first the system was truly rapid, but now it’s both slow and unreliable (“To Parisians it’s just nonsense”).

On the other hand, when the system is running, it’s full. And when it’s running well, it’s almost exhilarating – especially if one strides on it. (This TR correspondent’s four-year-old is sorely disappointed whenever the Gateway is out of service.)

With a flood of new airport construction, especially in Asia, walkway manufacturers continue pushing for the next breakthrough. Düsseldorf-based ThyssenKrupp Elevator recently unveiled a 7-kph walkway system that employs overlapping panels, replacing both the belt and rollers used in the Gateway. The panels telescope out at the front end to ease passengers up to full speed, then telescope back in for the step off.

ThyssenKrupp spokesperson Rembert Horstmann claims the firm has sold its first units, but also says they will remain “in development” with the buyers for at least six to eight months. Horstmann says they won’t be demonstrating the walkways for the media until they’re installed and running.

A wise decision, no doubt. If there’s one thing everyone has learned at Montparnasse, it’s that, as Pourquey puts it, “having a prototype working in a factory is a long way from having a proper unit operating in a public environment.”

Peter Fairley is a freelance writer living in Paris.