Planned engineering works

Londoners and visitors to the capital will be well aware of the fact that every weekend (except during the Olympics) for what feels like decades, tube lines have been closed or partially closed due to planned engineering works, which generally over run and cause chaos on a Monday morning.
Following an arduous day yesterday trying to navigate London with (I think) only the Bakerloo line running a full service, I decided to skip a planned trip to the Ideal Home exhibition today as just the prospect of another day waiting for replacement buses in the wind and rain was too much to bare.
Felt a mixture of relief and guilt when I spotted an army of workers on the tracks doing whatever it is they are doing down there.