This site is now Global Centre for Rail Excellence, currently under construction. There are various track diagrams online. This one is very clear: https://expedition.uk.com/project/global-centre-of-rail-excellence/
As you can see, the rail line enters from bottom left and feeds various test tracks.
There's a Wikipedia entry at https://en.wikipedia.org/wiki/Global_Centre_of_Rail_Excellence. This will be a significant facility for south Wales and the UK rail industry, and updating the map will be widely appreciated. Thanks. JML

Unable to answer "What surface does this road have?" – Alley – way/22751985 via StreetComplete 62.0:

Not sure what surface this counts as, it's flaky asphalt/fine gravel with stone down the middle

Attached photo(s):
https://streetcomplete.app/p/316913.jpg

Survey required to determine how this path continues

Is this number 35?
Is it The Square Pizza Company?
https://ratings.food.gov.uk/business/1692298

Path blocked by fallen trees

via StreetComplete 61.1

"Brown painted wood, seats 4, has backrest, no armrests."
OSM snapshot date: 2025-10-21T03:35:21Z
POI has no name
POI types: amenity-bench
#organicmaps android 2025.10.23-22-Google

'Caeathro Bach' yw'r lon bach rhwng Ffordd Waunfawr a'r cae peldroed