Security

Trolley 53 having fallen the right way made a good opportunity to snap the replacement front wheel, thought (by me) to be some kind of security device, present on most of Sainbury's trolleys..

Asking google about 'canst', which looks to have been embossed on the top of the wheel (top, at least as seen here), turns up reference 1 which looks promising. Further enquiries pending.

Reference 1: http://canst.ca/canst/.

Group search key: trb.