Here is a photo of the line at Chalford in 1997, not a weed on the tracks. Now any under-line springs have likely been there since the line was built, so it appears the greenery has somehow only developed since Railtrack/Network Rail came along.
The site of the station, looking towards Kemble. Chalford station was opened by the GWR in 1897 on the "Golden Valley" line between Kemble and Stroud, although the line had been in place since 1845. It was closed to goods in 1963, to passengers in 1964 and subsequently demolished.
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Some of the items in the current photo are pretty substantial. This is not just this year's growth. In the six foot small trees are starting to form. Is nobody in the per-way capable nowadays of coming along with a strimmer and dealing with them? I wonder what the front gardens of their houses look like.