A man has been arrested on suspicion of burglary after being found trespassing on tracks near Goodmayes station.
A police helicopter was scrambled and helped direct officers to where the man was.
Trains travelling towards Goodmayes station, in Goodmayes Road, Goodmayes, were running at slow speeds while the trespasser was located.
He was detained by police at around 1pm.
Some trains have been delayed by up to 30 minutes as Greater Anglia tries to get its services back on schedule.
Details of the alleged burglary are not known at this stage.
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