In the Buffalo area, where I grew up, there was extensive competition between several railroads along busy routes -- four main lines between Buffalo and Rochester, for example. Lines that were abandoned were usually redundant, duplicating the service provided by another that remained open. Rights-of-way were often bought by the transit authority, for possible use in a future rail corridor.
In Britain, some of the railways are being re-opened.
I finally got around to thinking about this...others have posted on the re-use of abandoned rail corridors in North America, but I don't think Journeymouse's question has really been answered. I'll do that nowIs anything similar happening State-side?