All of the above was brought home when a "smoke incident" shut down the subway system in Washington, D.C. See: Metro resumes old strategy to prevent more smoke incidents in tunnels
The solution? Clean out the tunnels, wash them down and prevent dust from building up and causing contact fires in the electrical system. This smells exactly like a deferred maintenance decision that was made to save money. Who cares if the tunnel is clean? The riders don't care, the board of directors doesn't care -- no one cares, until there's a problem. They have had two problems this year, so they will go back to cleaning the tunnels and defer something else.
This is not just a railway issue, these types of deferred maintenance decisions are rampant across all our infrastructures. You can bet that maintenance budgets were slashed during the recession and they have not been restored to their lackluster previous self.
As I've said before, our approach in the U.S. to critical infrastructure maintenance and repair is to fix on failure. This time it did not cost lives, but others have and will in the future.