Rail regulators yesterday set Network Rail a target of reducing disruption to passengers from engineering work by more than one-third over the next five years.

The challenge includes cutting disruption on the two main lines between Scotland and England. The Office of Rail Regulation said that, overall, disruption must be cut by 17% within three years and 37% within five years.

The ORR also told Network Rail it had to implement a programme of improvements to the way it manages engineering work, to reduce unplanned disruption when work overruns.

Three engineering overruns at Christmas and New Year caused travel chaos and led to Network Rail being fined a record £14m.

One of the overruns was on the west coast main line, which runs between London and Glasgow.

Continuing engineering work on this line has led to service disruptions on most weekends this summer.

The regulator said yesterday that Network Rail was missing its performance targets on the other principal London to Scotland route, the east coast main line to Edinburgh.

However, it welcomed the previously-published rail company performance figures which showed that 90.1% of trains ran on time from April-June this year, the best level for more than 10 years.

The regulator's chief executive, Bill Emery, said yesterday: "The latest figures are excellent news for most passengers.

"However, the regular closure of parts of the network for engineering work causes substantial disruption and inconvenience to many passengers and freight customers, as well as deterring others from using the network altogether. For rail to make its full contribution to our economy, it is important that this disruption is reduced signif-icantly. We have been taking steps to ensure this happens.

"We expect the railway to be kept open for business for as much time as is possible."

Network Rail will now implement a programme of improvements to the way it manages engineering work.

These will involve better risk management before projects begin and better contingency planning with train operators to minimise the impact of unavoidable delay to the resumption of full services.

Also included will be stronger on-site management to ensure any problems which do arise are identified quickly and tackled effectively.

Meanwhile, work to increase capacity and reduce journey times on the west coast main line, which has suffered closures over the summer, by December 2008 is making progress, said the rail regulator.

The ORR has been monitoring Network Rail's compliance with a 25-point plan to make improvements.

Mr Emery said: "We are monitoring the situation on the east coast main line, as performance on that route has suffered recently.

"A new joint performance improvement plan is due to be agreed between Network Rail and National Express East Coast in September. We expect this to address the current shortcomings."

Tracking progress

Among the statistics for rail travel in 2007/08 published yesterday were: