There were severe delays around lunchtime on the Tube's Hammersmith & City line between Moorgate and Barking due to an earlier signal failure at Bromley-By-Bow in east London.
This signal failure also led to minor delays on the Underground's District line.
Also, the Docklands Light Railway was suspended for a time mid-day between Deptford Bridge and Lewisham due to a suspect vehicle at Lewisham in south-east London.
One of the main Tube lines serving the Olympic Park was suspended as hundreds of thousands of people made their way to Olympic events
Tube trains to the Olympic Park suspended because of fire alert
PM on Olympic Transport