London’s Heathrow told passengers to allow extra time for their journeys to the airport Monday, with the three rail lines connecting the hub to the city simultaneously facing disruptions.

The new Elizabeth Line, as well as Heathrow Express and Piccadilly lines to Heathrow were all suspended for multiple reasons on Monday morning, according to Transport for London’s website. 

As of 12:30 p.m. in London, the Heathrow Express, which has a standard fare of £25 ($32) one way, was facing minor delays while the Elizabeth line had partially resumed services. The Piccadilly line still had severe delays due to an earlier fire alert. 

“Elizabeth Line services are beginning to resume and work is ongoing to resolve this as quickly as possible but we encourage passengers to allow extra time for their journeys,” a Heathrow spokeswoman said. “The airport is operating normally otherwise.”

Social media had posts from passengers earlier in the day saying they were stuck on Heathrow Express trains with no communication while others expected to miss their flights. 

The outage comes on a day when Prime Minister Rishi Sunak is due to hold a global investment summit in London that will have company leaders including Goldman Sachs’s David Solomon and JPMorgan’s Jamie Dimon in attendance.