The history of the WAGR A-class locomotives starts with the railway construction contractor John Robb who ordered a 2-6-0 locomotive from Beyer Peacock & Co, Manchester for the first section of the Eastern Railway from Fremantle to Guildford.  This locomotive was completed in 1879 and received the road number 3 (numbers 1 & 2 going to smaller tank engines).  No. 3 hauled the Eastern Railway opening train in 1881 and later passed into government ownership, becoming the first of the WAGR A-class locomotives.

The handsome WAGR A-class 2-6-0 locomotives were essentially repeats of the successful South Australian Railways W-class design which has been supplied by Beyer Peacock from 1877.  The boilers originally featured sloping smokebox fronts and Salter safety valves, and most of the class was supplied with a small 4-wheel tender.  The type proved well suited to passenger and mixed train duties of the day, with the A-class growing to 13 examples via repeat orders from Beyer Peacock & Co. plus one example supplied by Dubs & Co.

The A-class was superceded by the somewhat larger G-class 2-6-0 which was a further development of the same design. Several were used of various railway construction contracts and many passed into the timber industry after becoming surplus to WAGR requirements, while others were relegated to shunting duties at the end of their working lives.