A rush hour train was forced to be cancelled after drain covers were put on the track.
The 7.40am train from Norwich to London Liverpool Street was cancelled after the cover was put on the tracks near to Diss.
Greater Anglia has called this action 'dangerous' and warned that putting objects on train tracks can be fatal.
The company posted on Twitter: 'Someone placed drain covers on the tracks today near Diss, which caused delays to peak time services.
'This behaviour is so dangerous for everyone involved.'
Greater Anglia says that in 2016 there were 69 incidents where people 'dumped' things on the line.
A Greater Anglia spokesperson said: 'Some services between Norwich and London Liverpool Street were delayed or cancelled this morning after a train struck an object on the line.
'Investigations are on-going to establish how the object came to be there.
'We apologise to passengers who were affected by the delays. Customers are advised to claim delay repay compensation at www.greateranglia.co.uk/delayrepay.'
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