A roving Universal Hub reporter filed this report from Woodland this afternoon:

From first hand experience (I was there), a 2-car train (cars no. 3645 and 3843) had their pantographs damaged when entering Woodland station, possibly due to an issue with the overhead wire there. They sent a team over there pretty quick and they tied down the pantographs and shut down the cars. Shuttle buses showed up at Woodland around 45 minutes later.

And that's why there was shuttle-bus service along the D line today.