Delays are expected on some train services calling at Preston after a 'points failure' on the line this afternoon (Sunday, September 20).

Train operator Northern said the points failure happened on a section of track on the approach to Preston station.

It said services running through Preston might be delayed by up to 25 minutes or suspended altogether, with disruption expected until 2.15pm.

The first service to be affected was the 11.57am from Preston to Colne, with subsequent services delayed or cancelled.

A spokesman for Northern said: "Points failure at Preston. We can work around the points but this may cause some delays."

You can check the current status of affected services here.

What are 'points' and why do they fail?

Points are movable sections of track, allowing trains to move from one line to another. On some of the busiest lines, over 100 trains will pass over just one set of points every day.

Due to a points failure at Preston, trains have to run at reduced speed on some lines and services might be disrupted, say Northern

placeholder image — Due to a points failure at Preston, trains have to run at reduced speed on some lines and services might be disrupted, say Northern

Like signals, points can fail. They might get clogged with debris or ice, the drive mechanism might fail or, in hot weather, they might expand too much.

When points do fail, the system goes into ‘fail safe’ mode.

Because most points are monitored remotely, Network Rail can usually fix the problem before points fail. But when the problem is more serious, engineers can re-route trains to minimise disruption.