Commuters returning to work after the Christmas break this week will be faced with more disruption as train strikes continue into the New Year.
The RMT and Aslef unions will continue their walkouts over pay and conditions on January 3, 4, 5, 6 and 7.
There is also a bus strike affecting routes in south and west London planned for January 4 and 5 this week with further action planned for January 10, 12, 16, 19, 25 and 26.
Network Rail has urged passengers to avoid travelling, as 20% of trains are running.
RMT union leader Mick Lynch apologised for the action "dragging on" but accused the government of "doing nothing" about the dispute.
This week’s walkouts are the latest in a series of strikes across the rail network that have caused major disruption.
Will the strikes affect the London Underground?
According to Transport for London (TfL) most services, including most of the Tube, will continue to run.
However, there is some disruption expected on London Overground, the Elizabeth line, the Circle line and parts of the District and Bakerloo lines.
On strike days the District line will run a limited service from 7:30am and 6pm between Wimbledon and Parsons Green and Richmond and Turnham Green. A normal service will run on the rest of the line.
On the Bakerloo line no services will run between Queens Park and Harrow & Wealdstone.
There will also be a reduced service on the Circle line.
On the Elizabeth line trains will run between Liverpool Street and Shenfield (not stopping in Whitechapel), from Abbey Wood to Paddington and between Paddington and Heathrow/Reading.
There will be just two trains per hour in some sections, and services largely limited to between 7.30am and 5.30pm.
On the Overground there will be no trains before or after 7.30am and 6pm and there will be a reduced service.
The Night Overground will not run during strike days.
Elizabeth line strikes
Alongside the RMT and Aslef strikes, the TSSA union has also voted for strike action for its members working on the Elizabeth line.
The walkout is planned to take place on Thursday January 12.
Why are the unions striking?
RMT union members are holding two 48-hour strikes - on 3-4 and 6-7 January - after they rejected offers in a dispute over pay, job security and working conditions.
The strikes will involve 40,000 workers on Network Rail and 14 train operating companies.
Train drivers in the Aslef union are striking at 15 rail companies on 5 January in a dispute over pay.
Services across England, Scotland and Wales could be affected by the strikes.
Are the unions close to a deal?
RMT general secretary Mick Lynch has accused the government of “blocking” all attempts to reach a negotiated settlement.
"We have worked with the rail industry to reach successful negotiated settlements ever since privatisation in 1993,” Mr Lynch said.
“And we have achieved deals across the network in 2021 and 2022 where the DfT has no involvement.
"Yet in this dispute, there is an unprecedented level of ministerial interference, which is hamstringing rail employers from being able to negotiate a package of measures with us, so we can settle this dispute.
"We will continue our industrial action campaign while we work towards a negotiated resolution."