Watch out! Briefcases are on a roll - PATRICK WHITE

Every workday, chartered accountant Asifa Baig runs a veritable gauntlet of social disapproval.

Five days a week, she walks between her downtown Toronto office and Union Station, the regional train hub, and five days a week she endures frowns, scowls, shrugs and reprimands - both verbal and digital. "The dirty looks, they never stop," she says, taking refuge from swarms of commuters in a magazine shop steps from her train platform.

In the unwritten code of commuter conduct, few infractions are as egregious as Ms. Baig's daily stroll between office and train.

But it's not so much Ms. Baig that's the problem.

It's her rolling briefcase.

"I love it," she says. "I don't care what they say."

The wheeled briefcase has its detractors but also has a growing legion of admirers among the BlackBerry set. Laden with laptops, overstuffed file folders and electronic devices, urban office workers are finding relief for sore shoulders and wrenched backs in a nylon-and-metal caboose, making the bags a new bestseller for luggage makers.

Most major bag manufacturers, including Targus, Samsonite, Mancini and Victorinox, now carry at least one line of rolling briefcase. Prices range from just over $100 for a soft nylon model on casters to over $1,000 for a Kevlar bag with inline skate wheels.

Heys Luggage International, a Mississauga-based bag manufacturer, currently makes one model of wheeled laptop bag but has plans to meet increasing demand with four additional lines of roller bags next year.

For fashion-conscious female rollers, Heys is planning a briefcase constructed of polycarbonate plastic in such colours as candy-apple red.

But if customers remain hesitant about the stylishness of wheeling to work, their concerns don't seem to be affecting sales.

"We're completely sold out of Tumis," says Kelly Meehan, assistant manager at the Satchel Shop in downtown Vancouver, of one roller-bag brand that sells for up to $1,000. "They're beautiful. If I was a business girl, I would have one."

Small rolling baggage gained popularity for business travel in the mid-nineties, when workers began toting clunky laptops in their carry-on luggage. But it's only over the past five years that they began pulling the bags into the office place.

But popularity hasn't given way to acceptance. Wheelie bags remain an object of scorn in crowded office hallways and commuter byways. The bags are difficult to navigate in tight spaces and foot traffic tends to clot around stairwells when a roller-bagger stops to fold their tow hitch and lug their overloaded bag up the steps.

"People behind me on the stairs find that annoying," says Sakina Adenwalla, a consultant pulling her "office on wheels" into a train station elevator. "I see the odd scowl, that type of thing."

And because the bags have such a low profile, they can go unnoticed by some inattentive walkers. "I'm always tripping people," Ms. Baig says. "They're a bit of a nuisance."

Ms. Baig demonstrated just how irritated her fellow commuters can be with her bag by halting in front of some stairs and fiddling with her retractable handle. Several men in suits clumped behind her before letting out sighs of resignation and stomping around. "I literally stop traffic out there," she says. "And not in a good way."

Neval Greenidge, a marketing manager in downtown Toronto, carried a shoulder bag until late last year when the weight of hauling around a laptop, cellphone, GPS, file folders, diaries, keys and several file folders started to wear on his broad back.

With all the room in Mr. Greenidge's wheelie bag, there is a temptation to drag around more than he actually needs from day to day, "but at least I don't forget anything at home."

"This is much easier," he says, rolling his briefcase back and forth on the concrete floor of the Air Canada Centre. "Look at how smooth that is."

There's good evolutionary reasoning for rolling rather than carrying. Four-legged beasts might make decent pack animals, but when humans evolved to walk on two legs, our spines lost much of their load-bearing capacity.

"The dynamic of the spine was thrown off when we went vertical," says Andrew Drewczynski, ergonomics specialist at the Canadian Centre for Occupational Health and Safety.

"Our spines became unstable. Lifting a bag on one shoulder throws the spine off balance, so we compensate with compression of spine and the muscles that stabilize the spine are put under much stress."

The result can be a variety of ailments, but their common denominator is pain. With a roller briefcase, Mr. Drewczynski says, most of that pressure is carried by wheels.

Health benefits aside, some briefcase conductors find that their train-like stature actually grants them a wider birth in crowded spaces.

"I find that people actually get out of my way," said Ian, an accountant rushing for his midafternoon train. "And if they don't, I always have the option of running over their feet."