Back in the 60's or 70’s there were adverts for the London Underground with the catch phrase, "It's Quicker by Tube". So every time I see a picture like this it always reminds me of that advert.
This is just a bit further along the cycle track that was in yesterday’s picture, and there was originally a road bridge over the old railway line. The road actually climbs up to my village and I often drive over it.
The bridge was filled in when the line closed and this tube was added so that walkers and cyclists could continue along the journey. This view is only about a third of the actual tunnel length, but the capture the other way gives the tunnel but just a bright light at the end, at least you can see some greenery in this capture.
It's quite dark in this tunnel and there should be proper lighting in the ceiling where you can see a whitish square. Unfortunately the lighting wasn't working, with signs at each end apologising from the local council. As a 70+ year old pensioner I wouldn't be walking through here at night, its bad enough in the day.
I totally agree with the last sentence of your narrative.