BART will run longer trains in and out of San Francisco on the evenings of Friday, Oct. 28; Saturday, Oct. 29; and Monday, Oct. 31, to accommodate customers expected to be attending Halloween weekend and Halloween night festivities there. However, there will be no extended train service on any of the nights; service will end at the usual time. You can check schedules for the last train from your station using the BART QuickPlanner.
As has been the case for the past several years, there is no city-sponsored organized event in the Castro District, a historically popular Halloween destination. Instead, the city of San Francisco once again is encouraging people to celebrate at events in their own neighborhoods. For more info go to: http://www.homeforhalloween.com/
To avoid lines at ticket machines, buy a roundtrip ticket in advance or better yet, use a Clipper card and skip ticket machines altogether. More info at www.clippercard.com.