Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Walkers-ABB Suburban Multiple Units (200 Series) are a model of electric multiple unit used by Citytrain in South East Queensland Australia. The SMU 200 series EMU were originally introduced in 1994 due to a rollingstock shortage after an increase in Citytrain services. There are twelve in total and were built by Walkers Ltd. Maryborough and ABB Transportation, Switzerland.