It could finally be the end of the line for Pacer trains, as train operator Northern says they are no longer working its routes.

For 35 years, since they came into operation during the mid-80s, they have been a heavily-criticised part of the network.

The continued use of the train - known for being slow, bouncy and noisy – has been used as an example of the disparity in transport investment between the north and the south east.

Much maligned, they have been gradually withdrawn since December, with some planned to carry on services until their replacements arrive this summer as part of a £600m upgrade programme.

However, the latest measure was taken as part of timetable changes introduced by the company on Monday.

The changes have seen the introduction of additional services on some routes, but overall capacity on trains is significantly reduced to assist with social distancing.

A spokesman for Northern said: “There are currently no plans to operate Pacers on any routes as part of amended timetables being introduced this week.

“We still have some Pacers in storage and these will be retained as part of our contingency planning.”

The 102-strong fleet of trains was due for retirement at the end of December.

However, while many were expected to be withdrawn from service, David Brown, the firm’s managing director, said at the time that many of the locomotives would continue in the county until this month.

He said: “We’re delighted to be delivering on our commitments of removing Pacers from customer service and, at the same time, introducing 101 brand new trains.

“While Pacers have served the north well, we know they are old, outdated and not popular with our customers. For these reasons, when we won the right to being operating the franchise in 2016, we developed plans to remove them all from service.

“At least 55 of the Pacers will be permanently retired by the end of this year, with the remainder all gone by May.

“We are transforming our business and service to customers with a £600m investment in brand new and refurbished trains – and improvements at stations – that will provide everything a 21st century customer expects.”

Pacers were introduced in the 1980s as a short-term solution to rolling stock shortages on mainly rural routes, but have been used to serve busy commuter towns and cities for decades.

Speaking in October, Transport Secretary Grant Shapps described Pacers as a “symbol of the old railway continuing” and described their retention as “very frustrating”.

The only other operators using pacers in Britain are Transport for Wales and Great Western Railway.