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Graham.

%Profound_observation%
wrote in message
...
On 24 Mar, 20:49, "mark" wrote:
The warning says something like: Will come to a Sudden Stop at the Red
Line.

How does that work?

mark

Inductance loop buried in the ground at red line.Puts the brakes on.
Assuming you`re talking about shopping trolleys but just forgot to
mention it?

Assuming the trolley side is passive, it can't have too much
range can it?
Couldn't one just lift the trolley over the sub-surface coil, or
are trolley thieves not that bright?