Passengers on Greater Anglia’s rural routes are continuing to face massive disruption because of signalling problems – with investigators looking hard at whether there are issues with the new train fleet coming into service.

Leaves on the line are at the root of the problem - but the delays are only affecting Greater Anglia's rural services which have recently seen the introduction of new Swiss-built Stadler bimode trains.

Buses have replaced trains between Ipswich and Felixstowe and passengers travelling from Ipswich to Peterborough either have to travel via Cambridge or catch a bus connection between Bury St Edmunds and Ely.

The disruption comes after it was revealed that the Rail Accident Investigation Branch is investigating a very near miss between one of the new trains and a car on an automatic level crossing in Norfolk.

It is understood that engineers from the two companies are looking at three issues:

1)The operation of the signalling system across the network.

2)Whether the signalling system's sensors have been affected by adverse weather (ie leaves on the line being turned into a mulch causing short-circuits). This would also affect sensors controlling automatic level crossings.

3)Whether the new trains are able to be picked up by track sensors controlling signals and level crossings.

We have been contacted by Greater Anglia staff and rail experts who have said there is believed to be a problem with the trains setting off sensors - and this has forced the company to slow down its trains to ensure they run safely.

However passenger trains run by East Midland Railway between Norwich and Peterborough and freight trains to Felixstowe are able to operate normally - as are main line services travelling between the region and London.

Mark Budden, Network Rail Anglia Route Director, and Jamie Burles, Greater Anglia Managing Director issued a statement saying: "We are extremely sorry for the continued disruption to passengers using regional routes in Norfolk and Suffolk.

"Our engineers have been working round the clock to investigate why we are having problems with the track signalling system, which has led to us reducing the number of services we can run.

"We are examining every factor including components of the signalling system, the impact of leaf fall, and the interaction between the signalling system and passenger trains, old and new.

"We both fully appreciate that this situation is extremely frustrating for passengers and it is an absolute priority for us to get these problems resolved as soon as possible. We will provide a further update as soon we have more detail.

"We plan to restore normal services for our passengers as soon as we can. In the meantime, Greater Anglia is making sure that customers can still complete their journeys."

Ten questions for Greater Anglia and Network Rail over the issues faced by train passengers in the region over the last few days

1)We are being told that the disruption is caused by "signalling problems." Why is this only affecting services on rural routes, not on the main line between East Anglia and London?

2) Are the problems linked to the introduction of the new trains on Greater Anglia's rural services - in particular are they linked to a piece of equipment called a "flange lubricator" to reduce friction between wheel and track?

3) Are the "signalling problems" linked to the incident at the level crossing on the Norwich to Cromer line when a train came within a second of being in collision with a car and is currently being investigated by the RAIB?

4) If the problems are caused by signalling problems, why are freight trains continuing to run to Felixstowe and why are East Midland Railways trains continuing to operate between Norwich and Peterborough without disruption?

5) Is this problem going to take a long time to solve (like the problems with the new Transport for London Aventra trains)?

6) Has Greater Anglia trained enough drivers on the new trains and did you train them fast enough given the deadline to returning your existing rural trains to their leasing companies?

7) Why is the Ipswich to Peterborough service withdrawn when that is one of only two routes that cannot operate new trains?

8) When do you expect to know why there was a problem with the overhead collection arm (pantograph) at Elmswell last week and has this forced new checks on other trains?

9) How will the current issue affect the introduction of the new Intercity trains that are due to start entering service before the end of the year?

10) If the problems are linked to the introduction of the new trains, why did they not show up during 2,000 miles of testing over the region's rail tracks?