ORR's Chief Executive, Joanna Whittington said:
"ORR is concerned about the impact which producing a final timetable six weeks before travel will have on some passengers and freight customers.
"We have already called in Network Rail to explain the arrangements it has put in place to minimise the impact on passengers and freight customers. We will monitor its progress against the proposed recovery plan.
"We are writing to train companies reminding them of the need to keep passengers informed and are pleased to see train companies’ commitments to minimise the impact on passengers. We will be monitoring the performance of train companies in keeping passengers informed.
"We are investigating how this issue arose, industry’s delivery against its obligations and the ongoing response of all parties in minimising the impact on passengers. We will want to ensure that any lessons learned from this are properly addressed for the future."