Trains will run every 40 minutes between Lafayette and Pittsburg /Bay Point stations instead of the usual 20-minute weekend service because of the Central Contra Costa County Crossover Project, according to BART officials.
Delays of around 10 minutes will begin at 9 p.m. today and continue through the end of service on Sunday.
Normal BART service will resume Monday at 4 a.m.
Crews are adding tracks between the Pleasant Hill and Walnut Creek stations to allow trains to cross from one track to another. The project is expected to be completed in December.