Depot Incident on the Northern Line

Often you'll find that a very minor event - eg. just derailing one bogie - will block up the shed access roads and stock is trapped behind the affected train.

Now, I'm not saying that is what happened; I don't know but events like this when they occur in non-passenger service and on non-passenger lines tend not to feature in anything other than internal reports.

Depot 'whoopsies' IYGWIM are relatively commonplace by the very nature of the layout, unfortunately depending on the time of day the overall effect can be quite wide-ranging.