From BART:
The Contra Costa County Crossover Project will conduct final testing beginning on Friday Sept. 28 at 9 p.m.
Testing of the new train control system will require that the trains run in "Road Manual" between Walnut Creek and Pleasant Hill in both directions which will result in 5 to 10 minute delays for passengers.
We expect to complete the testing by Sunday night September 30, but may need to continue testing through October 7 if any unforeseen problems arise.
For up-to-date information check BART's real-time departures.