Why are trains delayed or cancelled? Common causes in Britain

Trains in Britain are mostly delayed by faults (signalling, points, the trains themselves, overhead wires), by weather, and by incidents on or near the line, and then the delay spreads, because fast, slow and freight trains share the same tracks, platforms and crews. A single failed set of points at a busy junction can make trains late across half a region within the hour. Cancellations usually follow from the same causes, or happen deliberately to get the timetable back to normal.

Faults with the track and the trains

These are the everyday causes, and the ones you'll see written on boards most often:

When signals or points fail, the railway's safety rules take over. Trains are given permission to pass the failed signals one at a time and move at caution, which is safe but very slow. That's why a fault that sounds small can wipe out a whole evening's timetable.

Weather, leaves and the seasons

The weather has a lot to answer for. Hot sunny days bring speed restrictions where rails could buckle in the heat. Heavy rain causes flooding and landslips. High winds bring trees down onto the line and can force blanket speed limits across a region. In winter it's frozen points and ice on the third rail used by electric trains across much of southern England.

Then there's autumn. Wet leaves get crushed into a slippery film on the rails, so trains struggle to grip when braking and pulling away, and drivers have to brake earlier. Network Rail runs special treatment trains to blast the railhead clean, and some operators run an autumn timetable to build in extra time. Our winter train travel tips cover how to plan around all of this.

Incidents on or near the line

Some delays come from outside the railway altogether:

• Trespass, or people on the line, which stops trains until the line is clear.
• Emergency services dealing with an incident, sometimes for hours.
• Animals on the line, from sheep to deer.
• A road vehicle hitting a railway bridge, after which the bridge has to be checked before trains can cross.
• Engineering works that overrun into the morning.

These are hard to plan for, and they're usually the reason a line closes completely.

Why does one late train delay so many others?

Because the railway is tightly packed. Trains follow each other a few minutes apart, cross each other at flat junctions, and share platforms at the big stations. If one runs late, it either holds up the trains behind it or misses its slot at the next junction and waits for a gap.

Crews and trains are tied together too. The driver of your train might be finishing a run on a late service somewhere else. The train you're waiting for might be the one that's stuck. That's how a problem near Birmingham can show up as a delay in Bristol or Manchester an hour later.

Why trains get cancelled

A cancellation is often a choice. When things go wrong, controllers sometimes cancel a train, or cut it short, so the following trains and the crews can get back to where the timetable needs them. You might also see a train told to skip some of its stops to make up time. Painful if it's your stop, but it stops the knock-on spreading even further.

The other common reasons are practical. "A shortage of train crew" means there's no driver or guard for that train. "Train not available" or similar means the train itself is somewhere else or out of service. Strikes, when they happen, cancel services across a whole operator.

What the board tells you

The departure board usually shows a reason with each delay or cancellation, written from a standard list the railway uses. That's why the wording is always a bit formal ("because of a fault with the signalling system"). Our guide to what Exp and Delayed mean explains the status words themselves.

If you arrive late, you can usually claim. Most operators run Delay Repay whatever the cause, though some pay from 15 minutes late and others only from 30. Delay Repay explained walks through it.

TrainTicker shows the same information at home. Its amber LED board reads Darwin, National Rail's live train information system, every 10 seconds, and shows expected times, cancellations with the reason given, and the station's notices scrolling along with the trains. It won't make the 07:42 run on time, sadly. It does mean you find out in the kitchen while the kettle's on. Have a look with the free live demo.