When the report said 'cleaner' I had this image of a lady not dissimilar to Mrs Overall from Acorn Antiques(not our very own!) being a bit too vigorous with the duster, then frantically looking for a brake handle as the train gathered speed!
Amazed that can happen in today's technological world. Derailing ? Don't the safety sensors cut excess speed and ensure the train stays on the track ? Clearly not then, but it ought. Traqins ought not be able to detatch from the rail except in exceptional circumstances.
When I was working night shifts at a railway station, we had a female carriage cleaner who had to start the engines on multiple units to power up the lights. She was absolutely terrified of doing what her Swedish counterpart seems to have done!