I went along to Paddington Station with my brother on Sunday as he was on his way back to Wales.
When we were sitting over coffees waiting for the train an announcement came over the tannoy asking "Inspector Sands" to attend some location or other and John told me that this is a code phrase used by public transport authorities to alert staff, and other agencies such as the police, to an emergency or potential emergency such as a fire or bomb threat.
No threat came to fruition as far as I can tell but it is interesting none the less.
Wikipedia says Inspector Sands is a descendent of Mr. Sands. "The code phrase "Mr. Sands" was used in theatres, where sand buckets were used to put out fires, as a code for fire. The word "fire" backstage would cause alarm to either performers or the audience."
Do you see how I did that, changing the subject from choo choos to mummery so I could boast that we'e got tickets to Present Laughter in the Old Vic the week after next? It just opened to universal acclaim see https://www.whatsonstage.com/london-theatre/news/review-round-up-andrew-scott-present-laughter_49338.html.