The station now has twelve tracks, but they are numbered 0 to 11 (east to west). The reason for this is as follows: up until a few years ago only tracks 1-11 existed; but in a refurbishment of the station, space was found to create an additional track to the east of platform 1. It was considered too disruptive to renumber all the other tracks in this busy station.

More Info: en.wikipedia.org