A series of mechanical and equipment problems caused major delays in Muni subway service for much of Monday morning.

Muni officials first announced delays caused by a power failure around 8:30 a.m. that affected service between West Portal and Van Ness stations.

Riders were advised to use surface transportation and bus shuttles were in operation between West Portal and Church streets during the service outage, which was not resolved until around 11:30 a.m.

The shuttles were dispatched around 10:15 a.m. However, an hour later, dozens of riders were still queuing on city sidewalks waiting for the service.

“So where in the world are these magical shuttle busses that have been promised?,” one rider, identified on Twitter as Mario Di Sandro, tweeted at 11:12. “There are a ton of us still waiting for one to show up.”

So where in the world are these magical shuttle busses that have been promised? There are a ton of us still waiting for one to show up. pic.twitter.com/f2zRgzoBX2

— Mario Di Sandro (@disandroid) November 18, 2019

Although the issue was resolved and service restored in both directions around 11:30 a.m., the agency tweeted that riders should “expect residual delays and shuttles are remaining in place until service balances out.”

Around 1:30 p.m., an M Oceanview train at San Jose and Lakeview avenues also stalled, although it was restored minutes later.

The latest delay was caused by a mechanical issue that stalled a J Church train at Montgomery Station around 2 p.m. The train was removed from service about 15 minutes later, but caused congestion between Embarcadero and Powell streets throughout the afternoon.

UPDATE: #Subwaysvc has been restored and moving in both directions, expect some residual delays and shuttles are remaining in place until service balances out.

— SFMTA (@sfmta_muni) November 18, 2019

Newly appointed SFMTA head Jeffrey Tumlin, who does not officially step into his position until Dec. 16, reportedly jumped into action Monday, riding his bike over to Castro Station to help direct passengers.

Biked to Castro to help direct passengers. Rail service good between Castro and downtown. Good bus shuttle between Castro and west portal. pic.twitter.com/xJ8AK2h6Qt

— Jeffrey Tumlin (@jeffreytumlin) November 18, 2019