Good read - historically the railroads depended on a system of demurage to make money (deliberate oversimplification alert): this included three pots of money paid by the shipper, one to the originating railroad, one to the terminating railroad, and a per-mile fee to earch railroad that moved the car in between. Railroads could even specialize in different types of traffic, the NKP in the midwest was a mover of fast freights between various eastern and western systems. Many major cities would have a terminal railroad jointly owned by the larger systems who's major job was to interchange traffic between the major roads. Demuragr was a regulated system under the ICC.Come the end of the ICC and deregulation this system changed unit traffic, whole blocks of cars or even whole trains just for a shipper, became more important then single car load demurage system. Infrastructure (tracks, yards, the physical stuff of railroading) changed to support this mainly via abandonment or spin off (the spin offs are usually called shortlines or class 3s). New stuff is rarely built but refurbishment or reconstruction of old infra is fairly common. And all that leads into the situation the article talks about.