Metcalfe's Law

I've often wondered why telecommunications or computer network planners could not apply their skills to the railways.
Metcalfe's Law states that the value of a network grows by the square of the size of the network. See useit.com
So a network that is twice as large will be four times as valuable because there are four times as many things that can be done due to the larger number of interconnections.
Conversely it follows that if you start partitioning the network (shutting lines and stations) the effect on the utility of the network can be quite devastating. You also lose redundancy (spare capacity) in the network - for example alternative routes should a route be blocked for any reason.
Travel planners are familiar with the concept of reducing travel time between two points on a given route increasing demand on that route but do they model the impact on the network?