Line issues affect Virgin's punctuality
Virgin Trains has labelled the infrastructure problems on its West Coast route between April and May as "unacceptable".
Overhead line and track issues meant the company was only able to run 82.9% of services on time in the period of April 29 to May 26.
Network Rail - responsible for the problems on the London to Scotland line - has already received a warning from the Office of Rail Regulation (ORR) regarding the need to improve punctuality on long-distance services.
However, Virgin said the ORR's action "does not deal adequately with the immediate issues".
It added: "We are concerned with the lack of focus on immediate improvement, as we and our customers must see short-term progress, especially as the Olympics and Paralympics will be a showcase for the industry."
Overall, train punctuality suffered a dip in Scotland last month, with train companies running 92.3% of trains on time during the same April to May period, down 1.4% on the previous year.
Copyright Press Association 2012