About 53,000 Queenslanders now call Greater Springfield home, but Sharpless insists the city is still less than halfway to reaching its designed capacity of almost 146,000, which would eclipse Darwin. Its total potential end value has been put at $88 billion, entrenching Sinnathamby’s position on the Financial Review Rich List. Springfield is one of a handful of the nation’s fastest-growing cities, alongside burgeoning communities around Sydney’s new south-west airport, and Melbourne’s Tullamarine-Broadmeadows region. They represent the front line of Australia’s urban expansion, real-time experiments in how the country might accommodate a much larger population. And they demonstrate that despite considerable…