Well there's no reason to think that's the entire pipeline, it's just the part somebody managed to map, which is why the ends don't connect to anything.

Here is the Bing Streetside imagery (a legitimate OSM source) for the Churchfield Road crossing which shows the marker pole: https://www.bing.com/maps?osid=3ca5f821-d9a0-4006-b135-aefee2f4106a&cp=51.814756~-0.164404&lvl=17&dir=116.25515&pi=-16.045433&style=x&v=2&sV=2&form=S00027