Commuters using the Elizabeth line were faced with disruption on Monday morning as emergency services responded to a casualty.
TfL reported severe delays were between Whitechapel and Shenfield with minor delays between Paddington and Whitechapel due to a casualty.
National Rail said someone had been hit by a train - with major delays also affecting Greater Anglia services from Liverpool Street.
The same issue caused the suspension of the Overground between Romford and Upminster.
Meanwhile, there were severe delays on the Circle and District lines due to cancellations of trains and a point failure at Whitechapel.
It comes as passengers have been warned that the Tube will be forced to close if strikes planned by Tube drivers go ahead on Thursday, November 7 and Tuesday, November 12.
Follow the latest updates below...
Major disruption expected until midday after person hit by train
11:00 , Matt WattsNational Rail has given more details on major disruption being caused by a person being hit by a train between Stratford and Shenfield.
The disruption is affecting the Elizabeth line as well as trains from London Liverpool Street.
Greater Anglia services between London Liverpool Street and Southend Victoria / Witham / Braintree / Colchester Town / Clacton-on-Sea / Walton-on-the-Naze / Harwich Town / Ipswich / Norwich are all affected, it said.
Whilst emergency services carry out their work, trains running between these stations may be cancelled, delayed by up to 60 minutes or revised.
Major disruption is expected until midday.
London Overground services between Romford and Upminster are also disrupted by this incident.
Severe delays on Circle and District lines
10:50 , Matt WattsThere are severe delays between Earl's Court and Wimbledon and between Upminster and Barking due to signal failures, TfL has said.
There are also severed delays on the Circle line due to trains being cancelled.
Severe delays on Elizabeth Line due to 'casualty'
10:44 , Matt WattsTransport for London has reported severe delays on the Elizabeth Line between Whitechapel and Shenfield with minor delays between Paddington and Whitechapel, while emergency services deal with a casualty.
It says there is a good service on the rest of the line.
