The London Underground and Rail, Maritime and Transport are holding last-ditch talks just hours before a three day strike, that could affect millions of people across London and surrounding areas.
Conciliation service Acas said the talks between the RMT and London Underground started at 10am.
RMT union members are set to walk out of their jobs for three days at 9pm this evening, in a long-running dispute with the London Underground over ticket office closures.
A two-day strike last week caused huge disruption, with roads clogged as people switched to other forms of transport.
More top news
A GoFundMe page was set up by the children's uncle to raise £15,000 for their funerals.
Lindsay Hoyle said his "family will never be the same" after the death of his 28-year-old daughter Natalie.
Police say they have traced four drivers who are thought to have hit the woman, and added that a fifth vehicle may also have been involved.