Avanti West Coast, which also operates on the West Coast route, has run fewer than half of its normal services since August 14.
Dozens of TPE trains are currently being cancelled at short notice each day, with at least 31 services not running on Tuesday.
⚠️ From Monday 12 September, we'll be bringing in a temporary amended timetable on the West Coast Mainline that aims to provide greater stability and certainty for customers. Please plan ahead and check before you travel.
ℹ️ For more details, visit: https://t.co/vInvw3ZQO9 pic.twitter.com/cKzdpIYCqg
— TransPennine Express (@TPExpressTrains) September 5, 2022
The operator, owned by FirstGroup, told passengers the disruption is being caused by “higher than normal sickness levels and ongoing industrial relations issues”.
The emergency timetables will affect routes connecting Manchester and Liverpool with Edinburgh and Glasgow, via Preston and Carlisle.
Nine of the 40 scheduled daily services will be axed, with a further eight only serving part of its planned route.
TPE expects the number of late notice cancellations to be “significantly reduced” under the measure.
Rail replacement buses will be used at certain times of the day.
The company’s service planning and performance director, Jerry Farquharson, said: “Our customers want reliable and punctual train services, and we are sorry that we have not been able to provide that due to the ongoing issues.
“In normal circumstances, we have enough people to fully operate our scheduled timetable; however, the combination of factors has put unprecedented pressure on our ability to operate a consistent service.
This temporary amended timetable for our services between the North West of England and Scotland will help us provide more stability and certainty for customers
Jerry Farquharson, TransPennine Express
“This temporary amended timetable for our services between the North West of England and Scotland will help us provide more stability and certainty for customers travelling on this route.
“We have put in place measures to communicate this revised timetable to any affected customers and believe that, by bringing this timetable in, we will help customers have more confidence and certainty in the delivery of our services.”
TPE’s conductors who are members of the Rail, Maritime and Transport union have been involved in a long-running dispute over pay.
The company’s train drivers who are in the Aslef union will join those from 11 other operators in striking on September 15, also in a row about pay.
Avanti West Coast blamed the need for its reduction in services on “unofficial strike action” by drivers.
The operator said it normally runs around 400 trains per week with drivers voluntarily working on their rest days – for extra pay – but that “dropped suddenly to fewer than 50”.
It announced on Friday that managing director Phil Whittingham will leave his role on September 15.