More train journeys will be affected by industrial action causing delays and cancellations across the network into October.
Throughout this year, the Rail, Maritime and Transport union (RMT) has taken strike action over pay, jobs, pensions and conditions, with the ASLEF union imposing overtime bans in a dispute over pay.
But now ASLEF, which represents train drivers, is walking out too.
When ASLEF members go on strike, it usually means there are no drivers.
When RMT members are on the picket line, it causes widespread disruption because people working in different jobs across the network are unable to fulfil their usual duties.
Here is everything you need to know:
Industrial action dates
ASLEF members at 19 train companies will be on strike on Saturday 30 September and Wednesday 4 October.
They will also have overtime bans across the network on Friday 29 September and between Monday 2 October and Friday 6 October.
RMT members are on strike, causing severe disruption across the London Underground, on Wednesday 4 October and Friday 6 October.
On full strike days there are likely to be few to no services operating, with disruption and later starts the day afterwards.
Which train lines are set to be affected?
Avanti West Coast
There will be no Avanti services on 30 September and 4 October.
Despite the ASLEF overtime ban, services should run as normal on 29 September and from 2 October to 6 October – with the exception of the strike day on 4 October.
c2c
There will be no c2c services between London Fenchurch Street and Southend Central or Shoeburyness on the two ASLEF strike days.
A reduced service will run – with two trains per hour during peak periods across all routes – on 29 September, 2, 3, 5 and 6 October.
First and last trains will be unaffected.
Chiltern Railways
No Chiltern Railways trains will run on any routes on 30 September and 4 October.
There will be reduced services on 29 September and 2, 3, 5 and 6 October, with trains not stopping at some smaller stations.
The London Underground RMT strike on 4 October and 6 October will mean Chiltern Railways services will be busier than normal.
CrossCountry
There will be no trains running on any routes on the two strike days – 30 September and 4 October.
Some services will be amended on 29 September and on 2, 3, 5 and 6 October.
East Midlands Railway
There will be no trains on 30 September and 4 October.
East Midlands Railway hopes to run normal services on 29 September and on 2, 3, 5 and 6 October, but last-minute cancellations could happen up until 10pm.
Customers are advised to check in advance if their train is running.
Gatwick Express
There will be no services at all on 30 September or 4 October.
A limited Southern service will run between London Victoria and Gatwick Airport on those days.
On 1 October and 5 October, the knock-on effect from strike action will mean services start much later – from 7am.
Non-stop Gatwick Express trains between London Victoria, Gatwick Airport and Brighton will not run on 29 September and 2, 3, 5 and 6 October.
Southern services will still serve the above stations but will be busier than usual.
Greater Anglia
Only limited services will run between Ipswich, Colchester, Southend, Stansted Airport and London Liverpool Street on 30 September.
On 4 October trains between Liverpool Street and Norwich will also run in addition to the above.
All Greater Anglia routes are due to operate as normal on the other affected days but will start later the day after full strike days.
Customers for Stansted Airport should expect only a train an hour on 30 September and 4 October – and services starting later than usual on 1 October and 5 October.
Heathrow Express
On the two strike days – 30 September and 4 October – there will be fewer trains going to Heathrow Airport and they will start later and finish earlier.
Trains will run between Paddington and Heathrow between 7.40am and 6.25pm.
Services between Terminal 5 and Paddington will run between 7.42am and 6.57pm.
And there will be trains between 7.47am and 7.02pm from Heathrow Central into Paddington.
The Elizabeth Line will service customers travelling from London to Heathrow.
LNER
London North Eastern Railway has said services will be “extremely limited” on 30 September and 4 October.
There will be “minor alterations” on the ASLEF overtime ban days – 29 September and 2, 3, 5, and 6 October.
London Northwestern
There will be no services on 30 September or 4 October.
On 29 September and 2, 3, 5 and 6 October buses will replace trains between Watford Junction and St Albans Abbey, and between Nuneaton and Leamington Spa via Coventry.
There will be fewer trains between Birmingham New Street and Hereford and Shrewsbury.
London Underground
Tube services will be “severely affected” or not run at all on 4 October and 6 October. There will also be no night tube on 6 October.
There will be disruption before 8am the day after strikes on 5 October and 7 October.
The Elizabeth Line, London Overground and tram services are not affected.
South Western Railway
On 29 September, 2, 3, 5 and 6 October there will be reduced services, with hourly trains only on the island line.
There will be “extremely limited” services on 30 September and 4 October.
There will only be trains between London Waterloo and Woking, Guildford, Basingstoke, and between Basingstoke and Salisbury between 7am and 7pm.
On 1 October trains are expected to run as normal.
Southeastern
There will be no trains on Southeastern routes on 30 September or 4 October.
Normal services are expected on 29 September and between 2 and 6 October apart from the strike day on 4 October.
Southern
On 30 September and 4 October, only one Southern shuttle between London Victoria and Gatwick Airport will run. They will be extremely busy and a queuing system will be put in place.
On 1 October and 5 October, the knock-on effect from strike action will mean services start much later – from 7am.
There will be fewer services on 29 September, 2, 3, 5 and 6 October with an amended timetable.
Thameslink
There will be no Thameslink services running at all on 30 September and 4 October.
On those days there is only the Southern shuttle between London Victoria and Gatwick Airport, but those services will be extremely busy and a queuing system will be put in place.
On 1 October and 5 October, the knock-on effect from strike action will mean services start much later – from 7am.
There will be fewer services on 29 September, 2, 3, 5 and 6 October with an amended timetable.
Transpennine Express
There will be no trains on either strike day – 30 September or 4 October.
Some early morning and late evening alterations on the days before and after the strikes are also expected.
West Midlands Railway
As with London Northwestern, there will be no services on 30 September or 4 October.
On 29 September and 2, 3, 5 and 6 October buses will replace trains between Watford Junction and St Albans Abbey, and between Nuneaton and Leamington Spa via Coventry.
There will be fewer trains between Birmingham New Street and Hereford and Shrewsbury.