There were two concrete slabs next to the line at West Croydon. Very heavy looking, maybe 300 - 400mm thick.
Having watched a 200T capacity Fleurieu Cranes' Demag set up for an hour or so at West Croydon, we almost missed the first of two slabs being placed at just up the line at Croydon.
Most impressive at Croydon was the careful attention being paid by workers to getting the slab correctly positioned with reference to the rails. Two Laser units were facilitating the measurements. Fine work from the crane driver at one point lifted the slab 20mm to suit the engineers/surveyors.
It looked like the workers will be bolting down rail mounts directly to the slab.
The two shots were taken at Croydon station around 11pm on Saturday the 7th of March 2015.