More than 40,000 railway workers are set to walk out from tomorrow beginning three days of national strike action.

Described as the biggest dispute on the network since 1989, the RMT union says it will 'shut down' the country's railways as its members protest again pay freezes and job cuts.

In a separate dispute over pensions and job losses London Underground RMT members are also set to join the strike for one day as well.

Here's all we know so far about the dispute and how the strikes might affect services.

When are the strikes?

The three strikes, each one lasting 24 hours, will take place on Tuesday, June 21, Thursday, June 23 and Saturday, June 25.

A further strike by London Underground union members is also scheduled to take place also on June 21, which is expected to add to the disruption.

Which railway workers are going on strike?

The strike affects RMT union members at both Network Rail and 13 train operating companies in the UK.

Network Rail is responsible for providing the infrastructure for the railway network and employs many people critical to the day-to-day running of the railway lines like signallers. While train operating companies take on the job of running trains on a small section of the network. The train operating companies with RMT members who have voted in favour of strike action are:

Avanti West Coast

c2c

Chiltern Railways

CrossCountry

East Midlands Railway

Greater Anglia

GWR

LNER

Northern

Southeastern

South Western Railway

TransPennine Express

West Midlands Trains (including London Northwestern Railway)

Why are RMT members going on strike?

This month's national rail strike is a dispute between rail bosses and union members over pay and job cuts.

The union claims Network Rail and the train operators have subjected their staff to 'multi-year pay freezes' while also planning to cut thousands of jobs, which it says will make the railways unsafe.

RMT general secretary, Mick Lynch, has said he will organise 'a sustained campaign of industrial action which will shut down the railway system' if he can't get a deal for his members, all of which - he says - are facing a cost of living crisis like the rest of the country.

The ballot for strike action opened at the end of April and the RMT says its members have voted overwhelmingly in favour of walking out.

How will services be affected?

The RMT union, which has called the strike, says it expects more than 40,000 of its members to walk out over those three days plunging train services into chaos.

Each strike will last 24 hours which is expected to cause significant disruption and might leave between only 15% and 20% of lines open for trains, which train companies may not be able to run and staff anyway.

Southeastern, which runs trains between Kent and the capital, is among the train operating companies affected and says it is currently working hard to understand what level of service it may be able to run.

On Monday evening, it issued a statement with a simple message of "do not travel" on Tuesday, Thursday and Saturday and warned of severe disruption on Wednesday.

A spokesman said: "Most of our stations and routes will be closed and we will only be able to run a severely reduced service. Please do not travel."

On the strike days, just 35 out of 180 stations used by Southeastern trains will be open.

There will be no rail replacement buses for stations which are closed.

Southeastern has warned passengers may be unable to board trains at stations where a limited service is running, especially at locations such as Ashford and Ebbsfleet.

The last trains back from London will be much earlier than usual, so there is a risk not everyone will be able to make their return journey, says the train company.

Services in between strike days are expected to be severely disrupted, especially in the mornings until midday and no services will run before 7.30am.

Timetable information for Friday and Sunday is not available yet.

Following the strike on Tuesday, Network Rail staff will need to do electrical supply checks before allowing services to run, especially in the East Kent area.

The checks cannot be carried out until Wednesday morning which means train services will start later, as follows:

Sheerness line

Estimated to run from 10.25 from Sittingbourne and 10.48 from Sheerness

Chatham mainline

Estimated to run from 9.37 from Faversham to Victoria and 11.21 from Rochester to Ramsgate

Estimated to run from 9.53 from Ramsgate to Victoria and 9.40 from Faversham to Ramsgate

High Speed via Faversham from Ramsgate

Estimated to run from 9.20 from Ramsgate to St Pancras and 11.25 from St Pancras to Ramsgate

High Speed via Canterbury West from Ramsgate

Estimated to run from 12.55 from Margate to St Pancras and 11.12 from St Pancras to Margate

Ramsgate to Victoria via Canterbury West

Estimated to run from 11.40 from Ramsgate to Victoria and 9.25 from Victoria to Ramsgate

Ramsgate to St Pancras via Dover Priory

Estimated to run from 13.12 from Ramsgate to St Pancras and 12.37 from St Pancras to Ramsgate

Dover Priory to Charing Cross

Estimated to run from 14.00 from Dover to Charing Cross and 11.40 from Charing Cross to Dover

Dover Priory to Faversham

Estimated to run from 15.18 from Dover to Victoria and 14.10 from Victoria to Dover

All services on Friday, June 24

All services are estimated to run from 7.30.

Which big events are affected by the strikes?

Alongside disrupting those who commute or use the railways for essential travel, a number of big events from music concerts to sports competitions are set to be affected by the strike action, which could leave hundreds of thousands of ticket holders now needing to find alternative arrangements.

Among the biggest events is Glastonbury between June 22 and 26, the England test cricket match in Leeds between June 23 and 27, the British Athletics Championships in Manchester from June 24 to 26, Elton John's concert in Hyde Park on June 24, Armed Forces Day on June 25 and the Rolling Stones concert, also in London's Hyde Park on June 25.

What about those already with train tickets?

Those with train tickets who had plans to travel but who either choose not to or who can't travel because their services become cancelled because of the disputes, should be able to claim a refund says the Rail Delivery Group. While Network Rail says it is now steadily putting in place plans to help people who may have already purchased train tickets for dates now affected by strike action.

This could include giving customers their money back, extending the validity of non-season tickets for the day before or up to two days after strike action or enabling travellers to use tickets on another operator or an alternative route.

You can read about the latest options that might be available to ticket holders, as train operators rush to establish which services they can run, here.

Could the strikes be called off?

Despite lengthy talks the RMT says it has so far not been able to secure a pay proposal nor a guarantee of no compulsory redundancies - both of which it wants before calling off the strike action.

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RMT general secretary Mick Lynch said: "Railway workers have been treated appallingly and despite our best efforts in negotiations, the rail industry with the support of the government has failed to take their concerns seriously.

"We have a cost-of-living crisis, and it is unacceptable for railway workers to either lose their jobs or face another year of a pay freeze when inflation is at 11.1pc and rising.

"RMT is open to meaningful negotiations with rail bosses and ministers, but they will need to come up with new proposals to prevent months of disruption on our railways."

Andrew Haines, Network Rail’s chief executive, said it is doing all it can to avoid strike action and will continue to meet with union members over the next two weeks in the hope of finding a way through.

He said: "We continue to meet with our trades unions to discuss their pay concerns and we’re doing everything we can to avoid strike action on the railway. We know that the cost of living has increased and we want to give our people a pay rise, but the RMT must recognise we are a public body and any pay increase has to be affordable for taxpayers and passengers.

"Travel habits have changed forever and the railway must change as well. We cannot expect to take more than our fair share of public funds, and so we must modernise our industry to put it on a sound financial footing for the future. Failure to modernise will only lead to industry decline and more job losses in the long run.

"There are a few weeks until the first strike is planned. We will use this time to keep talking to our unions and, through compromise and common sense on both sides, we hope to find a solution and avoid the damage that strike action would cause all involved."