Planned strikes by engineers on Southern Railway due to start this weekend have been suspended after a breakthrough in last minute talks, said the RMT union.
London Underground is set to resume a "normal" service today after strikes caused widespread disruption in the capital.
In a short message posted online, Transport for London managing director Mike Brown apologised for Thursday's "difficult day".
However, First Great Western trains will still be disrupted as a 48-hour strike continues.
Among the services affected will be trains between south Wales and London, which will run every hour instead of half-hour.
Services to Devon and Cornwall will also remain reduced from once an hour to once every two hours.
More information can be found on the First Great Western website.
A rail union have called the train services running during the current 48-hour strike unsafe.
The RMT union, whose members are striking in a dispute over job losses, safety and buffet cars on new trains, say First Great Western's current emergency "skeleton service", is "dangerously overcrowded" and staffed by people without the right training.
The union say they will be taking this up formally.
First Great Western denied that the trains are overcrowded, and told us staff working on them are fully trained.
"We've got fully competent managers working on these trains who would normally manage the people who are striking.
"Our utmost priority is keeping people moving safely and as quickly as possible."
"Our approach to keeping trains moving during this process has been sanctioned by the Rail Safety Standards Board - we would not be able to run these services if it hadn't been."
The 48-hour strike started on Wednesday night and is set to end at 6.30pm on Friday evening. Staff have been out picketing stations today.
"The anger of staff is clear as the action bites and it is now down to the company to recognise that and get back round the table to address the serious issues at the core of this dispute."
First Great Western say 10% fewer staff have walked out than they were expecting; however the strike has still affected almost 40% of their services.
London Underground bosses have contacted the conciliation service to help arrange fresh talks over the Tube pay dispute, which closed down the network today, causing travel misery for millions.
ACAS was asked to help get the two sides back around the negotiating table to avoid a repeat of the 24-hour strike.
TfL says the bus network is performing well, but traffic is heavy, and the rush hour was starting early for the second day in a row.
We thank Londoners for their patience today as we work hard to help them make their journeys. It's been very busy, particularly on the bus and road networks, although many people are travelling outside peak hours and walking and cycling. Our staff are working hard to help by providing maps, travel advice and other information. We are, as we always have been, ready to talk at any time to sort out this dispute.
Dozens of Tube trains lie unused at Boston Manor as a 24-hour London Underground strike continues to cause travel misery for workers.
Commuters have described "absolute carnage" as they attempted to get to work this morning while all Tube services across London were suspended.
One traveller said police had been called to a bus stop after the driver refused to move because the vehicle was so full.
Absolute carnage on 113 bus. Driver refuses to drive as bus is too packed! Police was called and they just arrived! #tubestrike
A spokesman from the Metropolitan Police said that while he was not aware of any reports, it would "make sense" with such large crowds in different areas today for them to factor any disruption into their policing.
Others said the roads were "mental" and many posted online details of their preparation to get to work.
Police are on duty at packed bus stops as London commuters battle to get to work amid a 24-hour Tube strike.
ITV News London's Simon Harris reports:
Commuters face trouble getting to and from work today as strikes cause delays on the rail and Tube network. Here's what will be affected.Read the full story ›
A picket line formed outside London Paddington this evening as Tube and rail strikes took hold.
All London Underground services were due to stop at 6.30pm for 24 hours, while workers on First Great Western are striking for 48 hours, disrupting trains to and from Paddington.
Long queues formed outside Tube stations as people tried to get home before the London Underground strike began.
Pictures from around London showed packed stations and huge crowds gathered outside ahead of the 24-hour strike.