And in spite of all precautions a railroad may take to prevent a total system failure that philosophy is hard to beat. Redubndancy, and the ability to take over dispatching from a center that has "gone down" is the key to keeping things moving. Placing all dispatchers in Jacksonville, Omaha, or Fort Worth may seem to placate the bean counters but can lead to total failure in some circumstances. If things go down in city X, city y may be able to take up the slack and keep the railroad fluid. It's the same line of reasoning computer specialists have off-site backups.
Sounds good in theory. In practice, if a Dispatcher is not qualified on a territory he can create situations that can take weeks to untangle. Just because one is qualified on territory A doesn't mean they know anything about operating territory Z.
In my dealings with NS, they have had failures at their office that handles VRE commuters from Alexandria to Manassas and they were dead in the water until those issues were fixed. I don't know what other territory that office controls, but their comments were that everything they controlled was stopped.
Today, no matter the industry, if the computer fails the activity comes to a stop. In most organizations there is neither the manpower or procedures available to do things 'the old way', especially since most of todays employees have no idea what 'the old way' was or how it worked.