Quebec's wacky racers: shoe, prawn or caribou?

The giant prawn, the vast shoe and the caribou need just a little push to get them started down the hill, but seconds later they pick up speed and the crowd goes wild as they hurtle past.

The soap box derby, in which competitors young and old race their outlandish homemade buggies or go-carts, is a sure-fire crowd-pleaser every year at Quebec's winter carnival.

The motorless vehicles must have four wheels, and these days the riders are required to wear seat-belts and helmets, but apart from that just about anything goes.

Many opt for complex drag car type designs, others prefer simplicity - just a box on wheels, but it could be quick. For some, it is more about aesthetics, a galleon with masts and sails may be less aerodynamic but it is visually spectacular.

First the carts have to be pushed up the narrow, cobblestone lanes of old Quebec City to reach the hilltop at Cote de la Fabrique for the start of the race.

2011 marked the 15th year of the derby and enthusiastic crowds flanked the hill, protected by railings, as competitors vied for glory in their gravity racers.

The categories - one for under 16s, the other for adult children - rewarded creativity as well as speed. Cash prizes were awarded by a jury for the quickest and the wackiest carts.

"We encourage original race car designs," carnival president Jean-Francois Cote explained.

The race was short - a mere seconds from start to finish - and the joy it afforded the hundreds of spectators fleeting, but some have been preparing for months for the big day.

"We worked on it for a year," Francis Sirois, a young volunteer at the Quebec Patro Roc-Amadour Catholic leisure centre, told AFP. "I was afraid of sleeping in this morning. We absolutely didn't want to miss the race."

The world's largest winter carnival, now in its 57th year, attracts annually 750,000 visitors from all over the world, according to organizers. It runs to February 13.

They don't just come for the soap box derby. There are dogsled rides, sleigh rides, sugar shacks, skating, sliding, snow rafting, music, an Arctic spa, ice sculptures and even an ice palace.

One highlight is a canoe race across the Saint Lawrence seaway. A South Korean all-female team competed in the event this year for the first time but turned back mid-way, judging the crossing - around ice floes - to be too dangerous.

Another event sees players attached to long metal poles across a field, allowing them to move only sideways, and only as a group, like a giant table soccer match.

The soap box derby is undoubtedly among the biggest attractions.

With some contraptions reaching speeds of up to 15 kilometers per hour (nine miles per hour), safety is paramount, and each cart is checked first to ensure it is functioning properly.

"We turn the steering wheel to make sure that wheels turn and we test the brakes - that's very important," a race official told AFP.

While there were no accidents this year, a few of the 31 racers did experience some technical problems.

The shoe car, for instance, won a prize for original design, but came in nearly last in the race as it limped across the finish line all out of step.