Train operators have been ordered by a regulator to stop misusing a process which removes services from schedules without them being classed as cancelled.
The Office of Rail and Road (ORR) said cancellations are at record levels, and there is “a further gap” between the passenger experience and performance statistics.
It found that operators are increasingly using a process known as p-coding, through which services can be axed as late as 10pm on the previous evening and not included in the timetables that reliability is measured against.
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For passengers, it means a train they expected to catch when they went to bed can disappear from the timetable by the time they leave for the station the following morning.
Such changes have historically been made to support the introduction of emergency timetables when poor weather or infrastructure damage has required major changes on certain routes.
But over the last year this mechanism has been used when there are not enough staff or trains available.
The ORR said it has written to all train companies telling them to “stop using this inappropriate approach”.
TransPennine Express is among the operators that have used p-coding.
The ORR also asked Network Rail to “coordinate the industry to come up with a better way of doing things”.
Until a permanent solution is found, the ORR said it is requiring operators to supply data on “resource availability pre-cancellations”, which it will publish to ensure “full public transparency”.
ORR director of planning and performance Feras Alshaker said: “We recognise this temporary mechanism was used to help passengers through a time of frequent disruption by telling them as early as possible when their train service was cancelled.
“But good passenger information can still be achieved while retaining full transparency, robustness and trustworthiness of the official statistics.
“As such, we need all train companies and Network Rail to come up with a more passenger-friendly method of making late changes.
“While this does not fix the performance problems themselves, it will support better passenger information while ensuring that the industry statistics remain a transparent and accurate representation of the service provided.
“This in turn will allow important service and investment decisions for the future to be based on the right information.”
A spokeswoman for the Rail Delivery Group, which represents operators, said: “We understand that reliability and punctuality of train services are top priorities for rail customers.
“The way that cancelation statistics are reported is set by the Office of Rail and Road, and train companies will operate within their framework.
“As an industry we will continue to work hard towards delivering more reliable and punctual services that our customers deserve.”