I took a ride on the Greenford-Paddington shuttle yesterday, in the
light of its imminent truncation to West Ealing, and noticed some
newish four-rail track between Drayton Green and West Ealing
junctions. All four rails were firmly clipped to the concrete
sleepers. I've not noticed it before -- does anyone know why it's
used?

https://www.flickr.com/photos/reclin...7667614586524/

More pictures in
https://www.flickr.com/photos/reclin...57667614586524