Yesterday morning saw the Central line service up the wall after an engineering train derailed as it crossed the points on the way into a siding at White City around the time of start of traffic.
Over-stretched and short-handed station staff - still not feeling the full benefit of their recent victory over staff cuts - had to deal with grumpy passengers for most of the day, while drivers had to deal with late running and changes to schedules.
Investigations are of course underway. As usual, these will probably look for an individual to blame, but even if the immediate cause is human error, humans make errors in the conditions in which they are made to work.
Engineering hours protection was privatised years ago, and private contractors always look for ways to cut cost, even if that means giving their staff too many responsibilities and distractions. And the organisation of the railway is so fragmented that it will be harder for the investigation to get to the root cause. With a variety of different companies involved, each will be trying to prove that it was another one's fault.
It is only by having an integrated, publicly-owned Underground that we can assess incidents like this honestly, with the sole motive being improving service and safety, not passing the blame in order to pass the bill.