Passengers will be warned about busy trains to encourage them to travel at quieter times from Friday.

Journey planning app and website National Rail will begin displaying red or yellow warning triangles next to services expected to be in high demand.

The system will use analysis of journey planning trends and messages from rail staff at stations and on trains.

Users will be asked whether they intend to take a particular service to help operators manage capacity.

It is hoped the system will lead to more people staggering their journeys as demand increases with coronavirus lockdown restrictions easing.

Passengers will also be able to keep updated about how disruption and overcrowding will affect their trip, and be provided with alternative travel options.

Alerts can be received via Facebook Messenger, with updates by text message and WhatsApp to be available in the coming weeks.

Train companies have also published the busiest times in the morning to travel to and from major stations.

These range from 5am-7am at Stratford, east London, to 8.30am-9am at Cardiff Central and Glasgow Central.

Robert Nisbet, director of nations and regions at industry body the Rail Delivery Group, said: “With social distancing meaning there is space for fewer people to travel by train, the rail industry will be using technology to help passengers stagger their journeys and stay safe while travelling.

“The eyes and ears of thousands of frontline staff will let us know if stations or trains are getting busy while cutting-edge data analysis will help us predict spikes in demand, giving passengers the advice they need in the palm of their hands.

“While people should only go by train if their journey is really necessary, those who do need to travel should sign up for alerts from National Rail and, before setting off, pop online to check the very latest information and avoid the busiest times.

“We also ask everyone travelling to wear a face covering to prevent the spread of the virus.”

Transport Secretary Grant Shapps said: “With capacity reduced to around one fifth of that previously seen on our railways, it is important that people work from home if they can, stagger their travel times to avoid crowds, and use other forms of transport wherever possible.

“But for those who need to use the train it is fantastic to see innovative digital services rolled out to help keep them safe while on the move.

“Harnessing data and new technology will be crucial both to enable social distancing now, and to modernise the network for the future.”

The Office of Rail and Road said 51 million fewer journeys were made on Britain’s railways in the first three months of the year compared with the same period in 2019.

The 11% decline is the largest quarterly fall on record and was blamed on the pandemic affecting travel in March.

– Here are the busiest times to travel to and from major stations during mornings:

Birmingham New Street: 6am-6.30am

Brighton: 7am-7.30am

Bristol Temple Meads: 8.30am-9am

Cambridge: 7am-8am

Cardiff Central: 8.30am-9am

Edinburgh Waverley: 7am-8.30am

Glasgow Central: 8.30am-9am

Glasgow Queen Street: 7am-8.30am

Leeds: 8am-8.30am

Liverpool Lime Street: 8am-8.30am

London Euston: 7.30am-8am

London King’s Cross: 7am-7.30am

London Liverpool Street: 7am-7.30am

London Paddington: 6.30am-7am

London St Pancras International: 6am-6:30am

London Victoria: 7am-7.30am

London Waterloo: 7am-7.30am

Manchester Piccadilly: 7am-7.30am

Newcastle: 7am-9am

Nottingham: 7.30am-8am

Reading: 7.30am-8am

Stratford (London): 5am-7am

York: 7am-9am