The most common coping strategy, though, is simply to increase the number of paying people per square foot of dwelling space

We've seen this before, when single family brownstone townhouses were converted to apartments in the big move to the suburbs.

There is a strong tendency in the US to stereotype a slum as an inner urban area, but the same thing happens whenever the property value drops below the replacement cost ... landlords begin extracting value from higher density renting to incomes lower down on the income ladder, while the property is allowed to depreciate.

And higher density in former suburban area where there is also out-migration implies abandoned housing.

If it dawns on people over the coming decade that a stopping rail service through the town can raise property values in an easy walk or park and ride of the station, and keep some districts out of the slum zone that are at risk of falling into the slum zone, the politics of establishing rail services will start to swing. NIMBY's will be converted into PIMBY's.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.