Network Rail is to be investigated by the Office of Rail and Road (ORR), which has accused it of causing delays and unreliability on some of the country's busiest routes.
Regulator ORR says that a five-year investment plan is behind target and over budget, and that less maintenance work has been carried out than planned.
Meanwhile, punctuality and reliability are poor on some routes - Southern, for example, which recently axed a stop and added an extra three minutes to the advertised journey time of one Brighton to London train in order to hit its targets.
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Last year, with passenger numbers rocketing, Network Rail embarked on a multi-billion pound plan to improve the reliability and efficiency of Britain's railways, as well as delivering a huge programme to improve people's travelling experience.
It has targets in place for the next five years covering value for money, punctuality and reliability, as well as minimising disruption for passengers while improvements are carried out.
But, says the ORR, it's falling behind.
"Network Rail has made a slow start in delivering on its enhancements and performance targets for [2014-2019] and we have asked it to demonstrate how it plans to get back on schedule to deliver on its commitments to 2019," says ORR chief executive Richard Price.
The planned improvements are set to cost £12 billion, and include new stations, electrification and bridges. However, says the ORR, Network Rail has missed 30 of its 84 planned milestones, with some projects facing delays or increased costs.
Track renewal is 7% behind plan; signalling renewals are 63% behind and overhead line renewals are 77% behind. And while performance on the East Coast Mainline and freight sector has been good, overall punctuality of train service performance is still stuck at 89.6% – 2.9 percentage points lower than the 92.5% target for 2019.
ORR has now launched investigations into both Network Rail's performance and its ability to deliver the ambitious programme of improvements.
Says Price: "This work will help identify the issues the company needs to address to improve train performance, increase capacity and deliver on its commitments to passengers."
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