Rail passengers are advised to check before they travel this week as only key train services will run if two days of heavy snow and extreme weather conditions forecast for the east of the region materialise.
Network Rail and Greater Anglia have been liaising closely with weather forecasters Met Desk in order to draw up contingency plans for the forecast spell of extreme weather.
Met Desk has warned of up to 30 centimetres of snow to fall during heavy snow showers overnight from Monday to Tuesday, and on Wednesday and subsequent days, when temperatures will rarely get above freezing so snow will not melt, and there is also a risk of snow drifts.
As a result of the extreme conditions forecast for Tuesday and Wednesday, Network Rail is concentrating on keeping main routes operating – Norwich to London, Southend to London, Norwich to Cambridge and Cambridge/Stansted to London.
There will be no services on rural routes: Norwich to Lowestoft, Great Yarmouth and Sheringham, and Ipswich to Felixstowe and Lowestoft. There will be no rail replacement bus service on these routes either.
Other routes will run with a reduced service in place - Full details are below.
If the weather is not as extreme as forecast, Greater Anglia and Network Rail will work hard to reinstate services and reopen lines as soon as possible.
Richard Dean, Greater Anglia Train Service Delivery Director said: “We apologise for the inconvenience that this reduced service causes customers.
“The last time such heavy snow fell in this region was over 25 years ago. In extreme conditions such as these, we work hard with Network Rail to keep key routes open, using snow ploughs, points heaters and mobilising all staff to clear snow off platforms and heat up and de-ice trains.
“Volume of traffic on some routes keeps snow from settling too deep, like on roads, but not on rural routes. We are committed to keeping our customers safe in all conditions and the last thing anyone wants is for customers to be stranded on a cold train in the middle of a blizzard in rural Suffolk or Norfolk.
“If the forecasts prove wrong, we will of course, do everything possible to get services up and running as soon as possible.”
All Greater Anglia staff have been asked to go to their local stations to help clear snow off the platforms, to keep stations safe for passengers.
A Network Rail spokesperson said: "We will be keeping a close eye on the forecast over the next few days and have plans in place should the extreme weather materialise.
"We will have extra staff working around the clock in order to keep main lines as clear as possible but while we will do everything we can to keep people moving, some lines may be closed and services will be subject to delays and cancellations, especially in the areas worst hit.
"We apologise for the inconvenience this will cause but the safety of our passengers and staff remains our number one priority."
These are plans for each route: