How do shopping trolleys grind to a halt when they cross the red line?

I've never tried to steal a shopping trolley (why would you want to?) but I have seen that sticker on them that warns that the trolley will stop immediately when it crosses the red line. Is this true, and if so, how does it work please?|||What do you mean steal a trolley .... I paid 拢1 for mine!!!








"The introduction of a hi-tech preventative measure aims to reduce the problem and Sainsbury鈥檚 has committed to installing a new electronic security system which will prevent people from taking the trolleys off site.





The system works on a radio signal transmitted from within the Horsham store via a sunken wire which will surround the car park and be marked by a highly visible red line.





All trolleys will be fitted with a device within the wheels and if trolleys are pushed over the wire, a brake comes on and the trolley can no longer be easily pushed.





The brake is de-activated and the trolley can be wheeled once it is pushed back inside the car park boundary."





|||iv stole a trolly before put a friend in to it and shoved him in to a river there is a lock that is activated by a magnet and under the red strip on the ground the is another magnet and when it crosses the lock shuts over and lock but if u smash that thinwheel on the trolly open and take the battery out it wont lock.|||it doesnt work. ive tried it at asda and the trolley just kept going. i think the plan is to work on our brainwashed state of mind . there are so many signs/ rules/ dont do this and thats, that *they* think we will stop at the line. try it. nothing happens and the world doesnt end. |||There is a magnetic barrier placed around the perimeter of a supermarket. When a trolley is pulled over one of these lines, it activates a locking device in the trolley's wheels.|||I KNOW!!! i have always wondered about that, maybe it's an electric current in the air? or a signal that is transmitted, maybe similar to an invisible dog fence? I'm way too embarrassed to actually try it and see... :-P|||a magnet buried in ground activates the brakes on trolly|||Stand-alone, proprietary RF sensor network system that is modular, scalable, and easily deployed to deliver multiple solutions |||The red line activates the brakes on the trolley which blocks the weels so you could take it but you would have to carry it because it won't ride anymore ;)|||Ha. You're one Kool kidd.





Well i've always wondered.





It's magic i guess.





I'll have a look later and see what others have wrote ; )|||It doesnt work


I tried plenty of times just to see what happens