The Rail, Maritime and Transport union (RMT) previously took strike action over pay, jobs, pensions and conditions, with the ASLEF union beginning overtime bans in a dispute over pay.

ASLEF represents drivers, whereas RMT represents members from lots of different sectors within the rail industry - including station staff and guards.

When ASLEF members go on strike, it usually means there are no drivers. When RMT members go on strike, there is widespread disruption to the network with lots of people in different roles going on strike.

Here is everything you need to know:

Industrial action dates

ASLEF members at 16 rail operators will refuse to work overtime - an action short of a strike - on the following days:

Monday 31 July

Tuesday 1 August

Wednesday 2 August

Thursday 3 August

Friday 4 August

Saturday 5 August

Monday 7 August

Tuesday 8 August

Wednesday 9 August

Thursday 10 August

Friday 11 August

Saturday 12 August

Which train lines are set to be affected?

Avanti West Coast

Avanti plans to run its normal timetable during the ASLEF action.

Customers who booked tickets to travel on strike days before the industrial action was announced can claim a full fee-free refund from their point of purchase.

Chiltern Railways

Chiltern Railways said during the ASLEF action, trains will be busier than usual, and there will be changes across the network's timetable.

It has also advised customers to "check before you travel".

A very limited service will be operating between 31 July and 5 August, and will be coupled with engineering works.

The journey planner is up to date with services for the strike days, it said.

CrossCountry

The train operating company has said during the ASLEF industrial action, "a small number of services may be subject to late-notice cancellation or amendment during this period".

East Midlands Railway

The network will be affected by the ASLEF overtime ban, with the operator telling passengers to check before they travel.

Greater Anglia

A number of services have been cancelled by Greater Anglia, due to the ASLEF overtime ban.

GTR

GTR, also known as Govia Thameslink Railway, is the UK's biggest railway franchise and operates Southern, Thameslink, Great Northern and Gatwick Express.

It said an amended timetable with fewer services will run from 31 July, with the operator warning that trains at peak times will be busier than normal.

It adds Gatwick Express will stop at Clapham Junction and East Croydon to help with passenger numbers.

LNER

London North Eastern Railway has said that it will be running trains with a reduced timetable on days affected by industrial action.

South Western Railway

A reduced service will run on the network, and some cancellations could be possible due to the ASLEF ban.

Passengers are advised to check their train before they travel.

Transpennine Express

The company says it expects to be affected by the ASLEF overtime ban from 31 July.

"We expect some services to start later and finish earlier than usual, and some journeys may be altered late the night before or on the day of travel," a message on its website said.

West Midlands Railway

On ASLEF action days, services will be subject to on-the-day changes.

Routes affected include Birmingham to Hereford and Birmingham to Shrewsbury.