Members of the Rail, Maritime and Transport (RMT) union, Transport Salaried Staffs Association (TSSA) and Unite started their 24-hour strike at 18:30. Aslef drivers were due to start their 24-hour action from 21:30.
Extra buses
In a separate dispute, First Great Western staff also walked out for 48 hours at 18:30, causing disruption to services between London, the west of England and Wales.
A TfL spokesman said: "On the buses everything is doing pretty well, people followed our advice and made their journeys earlier, there was some heavy loading but nothing extreme."He said there were 100 extra buses on the network and 200 would be laid on for Thursday.Traffic delays around Euston Road through the evening peak time and a unrelated protest at Parliament Square were causing problems, he said.Taxi drivers have been busier than normal during the strike.
`Surge pricing`
Bob Oddy, deputy general secretary of the Licensed Taxi Drivers` Association, said: "The public can rest assured they will not be ripped off by the licensed taxi trade who will only charge the normal fare which has been set with TfL."His comments come after the BBC found that car service app Uber had raised its prices through the day as demand for alternative transport increased.The practice, called "surge pricing", is normal among some hotels and airlines and is explained on Uber`s website, BBC transport correspondent Tom Edwards said.
At the scene
People had to beat the crowds by leaving work early and getting the last Tubes out of the city.But with noses pressed against backs and bodies crushed against the walls of shops, the realisation quickly dawned on them that everyone had had the same idea.The pressure started early. From 4pm, people were sweeping down the street, almost jogging to reach the Tube entrance.
But the crowds grew too quickly and plans had to be changed. Commuters consulted their phones, hoping to find an alternative route.Failing that, when buses were dismissed as too full, the favourite option seemed to be a resigned shrug of the shoulders and a plan to walk - trainers or not.
Ahead of the walkout, mayor of London Boris Johnson tweeted: "Tube strike politically motivated - union bosses need to explain why they refuse to put new offer to members - disgraceful - call it off!"
But the four unions involved maintain the new plans would be disruptive to their members` lives.