or: not authorized to access public freight networks


Industrial railway
An industrial railway is a type of railway (usually private) that is not available for public transportation and is used exclusively to serve a particular industrial, logistics or military site. Industrial railways may be connecting the site to public freight networks through sidings, isolated (sometimes very far away of public rail or surface roads) or located entirely within a served property. http://en.wikipedia.org/wiki/Industrial_railway

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Note added at 3 hrs (2012-06-06 12:17:32 GMT)
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[...] most industrial railways are short, usually being only a few miles/kilometers long. While these types of lines most often at some point connect via exchange sidings or transfer sidings to bulk mainline shipping railways, there are notable exceptions which are hundreds of miles long, which include the iron ore-carrying railways in Western Australia, or in China to transport coal, while in Canada there are the Quebec North Shore and Labrador Railway and the Cartier Railway. These lines can be thought of as dedicated shipment routes, where only the products of that industry require shipment between those two points, and hence a dedicated line makes more economic sense with only limited possibility of consolidation of shipment with other industries. http://en.wikipedia.org/wiki/Industrial_railway