Network Rail and Thameslink bosses face the London Assembly's Transport Committee later.
Rail executives will be questioned over recent overcrowding and chaos at London Bridge station.
Commuters faced weeks of disruption because of reconstruction work at the station.
More top news
A teenager has been arrested after a mass bomb hoax closed hundreds of schools across the UK.
The Metropolitan Police have confirmed the charge following his arrest on Sunday. He will appear at Wimbledon Magistrates’ Court on April 4.
Declan Donnelly will host the show alone when the show returns on March 31 following his partner Ant McPartlin's return to rehab, ITV says.