Original sentence: Fleet numbers: 49–81.The extra B Series railcar sets are expected to arrive from mid 2009 and allow the 12 two-car, A1/2 series railcar sets currently being used on the Perth-Clarkson line, to increase total capacity by 3,900 passengers, or more than 30 per cent, for the Armadale-Perth and Midland-Fremantle services
Edited sentence: As more sets become available, they will allow the remaining two-car A1/2 series railcar sets currently being used on the Perth-Clarkson line to increase total capacity for the Armadale-Perth and Midland-Fremantle services, with an overall increase of 3,900 passengers, or more than 30 per cent.Fleet numbers: 49–82.The first three B-series railcar sets were introduced on the 28th of June, 2009 and have allowed some of the A-series trains to be transferred to the Midland-Fremantle line