More lichens on rails

I walked a different section of the disused railway today and found parts of the old rails with a different selection of lichens, algae and rust patterns - see my photo of 3 days ago. I really liked this example. I've tried to track down more information on lichens growing on metal and other unlikely substrates, with great difficulty. I eventually came across a fascinating paper on "Rapid assessment of the diversity of 'vehiculicolous' lichens on a thirty year old Ford Bronco truck in central Puerto Rico". This paper describes how a group of lichen specialists examined the long abandoned truck and identified 40 different lichen species, including 9 species new to the country! Mentioned in the paper is a study of an old Lada in southern England that had the UK record of 21 species. I wonder now how my railway line is measuring up.