The station has 13 terminal platforms, numbered 1 to 12 and 14 from south-west to north-east (left to right as seen from the concourse). Platforms 1 to 8 are below the original three spans of Brunel's train shed, platforms 9 to 12 beneath the later fourth span. Platform 13 was decommissioned in December 2016 to permit lengthening of platform 12 for 10-coach trains. Platform 14 is within the Metropolitan Railway's old Bishop's Road (Suburban) station to the north-west. Immediately alongside are through platforms 15 and 16, used by the London Underground's Hammersmith & City and Circle lines. The current operator, Great Western Railway, assigns numbers to the pocket timetables it publishes, and its services to Bath, Bristol, Weston-super-Mare and South Wales are in timetable number 1.