RAIL passengers who have had easy weekend rail trips to London over the summer are in for a nasty shock from next month as a major engineering project gets under way.

RAIL passengers who have had easy weekend rail trips to London over the summer are in for a nasty shock from next month as a major engineering project gets under way.

And services between East Anglia and London are likely to be disrupted at weekends throughout 2009 as Network Rail struggles to renew old electrical equipment in Essex.

Some of the overhead wires - or catenary - on the line dates back to the 1940s. It has been repaired and upgraded over the years, but now it has to be replaced.

The fragility of the existing wires has been shown up several times recently when the wires have come down causing major disruption for passengers.

Network Rail is spending tens of millions of pounds completely renewing the system - but the work can only be done at weekends.

That means trains will be replaced by buses during many weekends over the next 12 months, a move which will especially hit leisure travellers.

Earlier this year there was disruption to rail services most weekends, but the main line has remained open most of the summer as engineering gangs moved to other lines in Essex.

However weekend closures are due to resume next month - buses will replace trains on part of the route on October 12 and then again on many weekends during the run-up to Christmas.

Then next year the major work to replace wires between Bethnal Green and Shenfield is due to be completed.

Much of this infrastructure dates back to pre-nationalisation days when the line to Shenfield and Southend was “wired-up.” The line from Shenfield to Colchester and Clacton was electrified in the late 1950s.

New wires and posts to carry them will be installed all the way between Liverpool Street and Shenfield.

A spokesman for Network Rail said: “They've been up a long time and they really are now life-expired. It is going to be a major project and there will be some disruption, but it needs to be done.”

Network Rail was unable to give precise details of when the line would be closed at weekends, but The Evening Star understands passengers are likely to face weekend disruption for much of 2009.