The new trains introduced on Greater Anglia’s rural routes were not the cause of the signalling problems that have plunged services into chaos over the last few weeks, the company said today.

Their engineers have been working with Network Rail since signalling problems first hit services at the end of November.

They are now satisfied that the signalling problems only affect the Norwich to Sheringham line in Norfolk - and that all trains that use that line, old diesel units and freight trains travelling to North Walsham - have been affected by it.

There have been no problems with signalling on any other lines in the region, and Greater Anglia is now trying to reintroduce normal services on all of these.

However the problems of the last three weeks have delayed the commissioning of new trains and training of drivers, so it will be a few days before a normal service is introduced everywhere.

And the Ipswich to Peterborough service could remain suspended until early in the new year because it has not been possible to carry out route testing with the new trains.

Greater Anglia officials had to introduce speed restrictions and extra tests on the new trains because they were the one new factor that had been introduced into services before the problems became apparent - officials say if there had been a problem with them it would have been irresponsible to run them normally without making changes for safety reasons.

A spokesman for Greater Anglia said: "We are very sorry for the major disruption to services on our regional lines recently. These delays and cancellations were not due to the performance or design of our new trains. We were unable to run our normal train service due to signalling issues.

"We are now able to operate the normal timetable on our rural branch lines again, except for the Norwich to Sheringham line, so the majority of services have been reintroduced.

"Unfortunately, last week we were unable to carry out testing and driver training due to the problems, which slightly set back the roll-out plan for our new trains, thereby resulting in ongoing cancellations on the Ipswich to Peterborough line.

"However, that programme has now resumed and we're hoping to introduce further new trains on our network soon and restore a full, reliable service across all our regional routes as quickly as we can."

A spokesman for Network Rail repeated their comment from the end of last week: "We are running a series of rigorous tests to identify the root cause of the problems, including examining the impact of leaf contamination, the level crossing mechanisms and how trains' wheels connect with the track signalling system."