Irrespective of why its there, lets just say I'm happy as it gave me something to take pictures of!
The material being moved is crushed demolition rubble from some old concrete buildings which were demolished some time ago - possibly from the neighbouring Neptune yard which has been flat for a couple of years now.
The first picture is actually the more recent one, the pink structure you can see behind the ADT in the 2nd image is the rail-mouted travelling gear for a 180ton capacity lever luffing crane built by Clarke & Chapman. These cranes (two of this type were on site) have been dismantled and are to be ferried off to India to equip a shipyard there.
