Image above of train from current fleet at left and a new train car, right, still in testing mode

As of this week, BART riders on platforms and stations may get a glimpse of train cars from the new Fleet of the Future, as the first pilot batch is tested on mainline tracks during business hours.

But these are test trains only with staff aboard; they are not certified yet to carry public passengers.

The trains will have an "OUT OF SERVICE" indication on them and the platform destination signs will read "TEST TRAIN - DO NOT BOARD."

The trains may make stops at stations and doors may open, depending on which testing is being performed. If doors are open, test personnel or barriers will be in place to prevent inadvertent passenger entry.

Already, the trains have been put through their paces on a test track, and have been doing test runs during the overnight hours when no passenger trains are running.

This marks the first time they'll be running tests during business hours on the mainline, albeit with no paying passengers aboard. Not all of the train cars will be out at the same time, because some are being used off the main tracks for operator training.

Once testing is complete with the batch of pilot trains, they will be put into service for passengers, and delivery of more new train cars will ramp up. For the full schedule and lots of other information about the new trains, visit www.bart.gov/cars