Often referred to, but from my limited experience rarely seen nowadays. I have read it was a cared-for route railway workers could transport their tools, materials, or cycle to and from work. Today it's difficult to find a surface that would fit that description.
http://www.deathbyhealthandsafety.co.uk/jungleron/definitions.html Is an interesting article, and has a couple of telling pictures.
So if I want to reinstate a working cess, please can anyone point me to some reference documents, or otherwise provide an answer?