Geocaching with friends

Had a longer walk than usual on our geocaching trip today.
I've wondered what these towers are for years and today I asked a passing dog walker if he knew. He told me the railway line runs there so I think he meant they are ventilations shafts for the tunnel below.
Today we had no rain but it was one of those damp days when everything is wet through and never dries. We had a fair bit of mud on the trail but nothing we were not equipped for.
We found all the caches which was good.
We've not cached for weeks due to storms and other bad weather so it was good to get back on it.
Update -  I checked about the ventilation shafts and some had posted online that they are ventialtion shafts for the Upholland Railway Tunnel on the Wigan to Kirkby liune that runs underneath.