What are these parts on the ECML Bridge over the Idle at Retford?

[eastglosmog]

Dave

An interesting photo.  I've seen  pictures of what that bridge (or one very like it) looked like before the centering was put up - makes you wonder how it stayed standing.  It's what 10mm/m or so of stretching produced by mining subsidence can do! Not that the bridge at East Retford would ever have been subject to that amount of movement, the seams being much deeper and the NCB taking a bit more care by then.

Like you, I wondered whether the needles were there for emergency work on the pier footings.  However, as an engineer with considerable experience of water flow, I would not install them for this purpose.  The needles will be very prone to collecting floating debris during floods which will form an obstruction to flow.  This debris would impose loads on the piers and by restricting flow width, increase the velocity, thus increasing scour around the footings - thus causing the very problem they were intended to deal with!

Incidentally, I have been doing a bit more delving on the mining issue.  The area was in the take of Bevercotes Colliery.  This opened in 1965 and was highly mechanized with fast moving coal faces and remotely controlled mining machinery.  The East Retford area was only investigated by the NCB in detail in the mid 1970s, and mining only ever got anywhere near in the early 1990s, shortly before the colliery closed in 1993.  Hence my guess of installation of the needles in the 1960s may be a bit early - could well have been in the 1970s to 1980s (assuming, that is, that the steam engines visible in the OP's photographs are engines like Flying Scotsman, Tornado or the like having a spin on the ECML).