The 6300 series began revenue service in June 2023. The Transbay commuter coaches were built by Motor Coach Industries (MCI). This was redesigned with a mid-cabin door providing better accessibility for riders with mobility devices to the low-floor vestibule. Another ADA innovation is the Q'Straint: Quantum Wheelchair Securement Station, a button that starts an automatic locking sequence where the Q'Straint’s arms safely secure the wheelchair in place. With better accessibility, rider, and operational improvements, this will improve transit service across the Bay.