Every day at one o’clock, a locomotive, heard but not seen, makes its way through the lobby of CarriageWorks, an old Sydney rail yard recently transformed into a performing arts center. The sound sculpture by Nigel Helyer, called GhosTrain, haunts the space it runs through. While the installation presented by Performance Space only sounds for 90 seconds, the complexities implied by the work encourage thoughtful engagement with the ideas of sound and history implied by its reference to acoustic ecology and the idea of a soundmark.