A Pacer is running on the York to Scarborough railway line for the first time in 15 years today

Despite Pacers being withdrawn from service this year by operators Northern, one of the 1980s-era British Rail relics was spotted travelling on the York to Scarborough line by eagle-eyed observers on Wednesday.

Northern do not operate passenger services on the line - all trains are run by Transpennine Express - and trainspotter John Sparrow, who tweeted a photo of the train passing Bootham Junction, estimated that it has been around 15 years since a Pacer was last seen on the route and 10 since a Northern train had gone beyond the eastern limits of York Station.

The Pacer graveyard: This is where Northern's trains go to end their livesThe Class 142 Pacer, registered 142068, is thought to be the only one of its generation still in service on Northern's network, with the others of its class having been retired in the past few months.

The Pacer spent the night at York Station, leading to trainspotters to speculate that it was due for a 'special working' the next day. It left York just after 7am - almost half an hour after it was scheduled to depart.

Yet realtime train information revealed that the train was travelling as an empty stock movement.

It has now been confirmed that the Pacer was being used as a driver training vehicle by Northern, who will begin to operate passenger services between York and Scarborough via Malton in May, when a new timetable comes into force. Drivers require route familiarisation before they can take control of a service.

A spokesperson for Northern said: “We have used a Pacer on the route between York and Scarborough to assist with training as part of our plans for the introduction of new services on that route later this year.”

The National Railway Museum's Pacer has arrived - ironically earlier than expectedWhat is happening to the Pacers?

The Pacers were introduced as a temporary stopgap solution to stock shortages but ended up serving Northern routes for 40 years before their phased withdrawal began at the end of 2019.

They are being decommissioned and scrapped at the CF Booth metalworks in Rotherham, one of the few firms in the UK capable of dismantling old rolling stock. The parts and metal could end up being shipped overseas.

Northern leased 102 Pacers from Angel Trains, and the first one was removed from service last August, with three more following in the autumn. Their retirement has been delayed due to ongoing problems with electrification of the network and the manufacture of new rolling stock. They are sent to a storage depot in Worksop before being taken for decommissioning.

Northern have promised they will disappear from Yorkshire routes in 2020 despite the 'temporary retention'.

The trains - known for their rattling motion, cold, dated interiors and noisy engines - were created by attaching bus bodies to rail bogies, and the passenger experience is frequently likened to being on board a bus.

The National Railway Museum have accepted a donated Pacer - the first of the Class 142s to be produced - to add to the national collection. It is currently at their Locomotion site in Shildon, County Durham, where it will eventually run on a short test track, giving rides to visitors.

The Chasewater Railway heritage line in Staffordshire has also bought two Class 142 units for preservation.

Charities and community groups were also invited to bid for Pacers, and among the competition winners were men's mental health charity Platform 1, who are based at Huddersfield Station and will convert the train into a kitchen to teach cooking classes.

Airedale NHS Trust were awarded a Pacer to use as a patient space and Fagley Primary School in Bradford will turn theirs into a science lab.