The number of train cancellations in the region due to train faults has doubled in the last four years, it can be revealed.
Brake and door system faults, technical failures and other problems were behind the 805 cancelled Greater Anglia services due to a train fault in 2016.
This was a 93% rise from 418 in 2013, Freedom of Information (FOI) data uncovered from Network Rail showed.
Greater Anglia insists its £1.4 billion revamp, in which its entire fleet will be replaced with 169 new trains, will improve reliability.
Greater Anglia pledged the revamp after winning a nine-year franchise last summer.
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A Greater Anglia spokesman said: 'We run about 429,000 services a year and the average percentage cancelled due to train faults over the last five years is less than 0.16%.
'However, we know that even one cancellation is inconvenient to customers, so we are investing on improving our reliability.
'Our award-winning engineers work hard to maintain and improve the performance of our trains, which are now going longer distances between faults.
'In 2019 we will start to replace every single one of our old trains with brand new state-of-the-art trains which should further improve our reliability.'
Separate data showed Greater Anglia's intercity trains – Norwich to London Liverpool Street via Ipswich – cover 191,000 miles without a breakdown.
Class 321s and 360 trains on the same line are totalling 35,000 and 60,000 miles respectively without breaking down.
The FOI data found cancelled services involving doors and brakes issues totalled 518 between 2013 and 2016. It doubled from 84 in 2013 to 164 in 2016.
For services running to, or starting from, London Liverpool Street, the figure rose from 252 in 2013 to 452 in 2016. For all Ipswich services, it rose from 43 to 108.
Derek Monnery, from the Essex Federation of Rail Users, said cancellations due to train faults are 'incredibly frustrating'.
He said: 'Due to the uncertainty about the franchise, the trains are old and beyond their sell by date.
'Hopefully the new trains will improve reliability. Greater Anglia seem up for the challenge.'
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