When Chicago had a small leak in an empty tunnel, it increased and started to flood. Eventually it poured throughout the entire tunnel network. Over 250,000 people had to be evacuated from the buildings above the flood which caused almost $2 billion in damages.  To dry the tunnels, this took an additional 6 weeks. Imagine if this occurred in Melbourne’s underground…. the cost in lives and infrastructure would be enormous. Technology in the inflatable arena has stepped up to the plate to provide an innovative and immediate solution to this very serious threat to Melbourne’s underground section of its train system.  To isolate or seal a part of a train system’s underground tunnel is imperative and must be able to occur at any given moment before flooding can become a danger and a threat.  To attempt to retrofit removable doors will be too costly and tie up the transit system for a long period of time Because underground tunnels have uneven...