West Coast main line company Virgin Trains is to take action against Network Rail (NR) over what it claims is breach of contract concerning train punctuality.
Virgin's parent company Virgin Rail Group (VRG) said that any fine imposed on NR by rail regulators for failing to meet punctuality targets should be in the form of customer improvements.
Both the Office of Rail Regulation (ORR) and Virgin have been unhappy with NR's recent punctuality record, with the ORR announcing today that NR missed its long-distance train punctuality targets for 2012/13 by 4.5 percentage points.
Virgin said it was "preparing enforcement action to bring punctuality improvements, following sustained poor performance by Network Rail, which we believe is a breach of contract and has deterred some customers from travelling and damaged our business".
The case will be heard by a rail industry body - the Access Disputes Resolution Committee.
VRG chief executive Tony Collins said: "NR has consistently failed to deliver what it is contracted to deliver. That has directly affected customers' experience, and their impression of rail travel.
"So any penalties levied on NR should be in the form of tangible improvements that customers benefit from. There is really no benefit to NR, customers or VRG in having money leave the industry."
He went on: "We have spent hundreds of millions of pounds on a fleet of reliable trains and we pay NR nearly £200 million a year to maintain the West Coast line for us. We feel that we are not getting value for money in this respect and our customers have been let down and deserve more consistency.
"We have made our case strongly over many years to NR, the ORR and government. But reluctantly we have taken this difficult decision on behalf of our customers."
Virgin said NR had missed targets agreed with Virgin Trains over the last two years, and punctuality stood at 85.7 per cent in the most recent four-weekly period ending May 25, against a target of 88.0 per cent.
Virgin said that more than 70 per cent of delays were as a result of NR infrastructure issues, with fewer than 15 per cent caused by Virgin Trains problems. The remaining delays were caused by other freight and passenger operators, Virgin said.
It added that in the current financial year, starting in April, NR delays had added more than 1,000 hours (65,000 minutes) to Virgin Trains' customer journeys.
A Network Rail spokesman said "We are not satisfied with the current performance of our infrastructure on the southern end of the West Coast line, which is one of Britain's most vital rail arteries, and we are working closely with Virgin and our other customers to improve the situation.
"Today, there are twice as many trains using this line as a decade ago and, just like a busy motorway during rush hour, more trains mean that if something goes wrong, the knock-on effects can be significant."
The spokesman went on: "Last year, we invited Virgin's chief operating officer Chris Gibb to join us on secondment so that he could better understand the operational challenges we face in running ever more trains on what is Europe's busiest mixed-use rail line.
"His hugely insightful report made a number of recommendations, all of which we have accepted and will implement."
The NR spokesman continued: "We have identified almost £40 million of investment aimed at improving performance by targeting some of the most common causes of delay and our engineers have commissioned Siemens, one of Europe's leading engineering and technology companies, to work with us to implement a programme of improvements to overhead power lines.
"We have also begun to erect better security fencing to cut delays caused by trespass and vandalism, which is a key concern. Some of the measures will benefit passengers in the next few months while others will require work over a sustained period of time."