Sadly, all has not been well with the viaduct, which dates from 1844. The structure is listed on the Historic England Register of Buildings at Risk.
As is well known, the viaduct doubled as an aqueduct, carrying , below the trackbed, the leat which powered Carmears incline (which brought wagons up from Pontsmill). In recent times, the leat has been flooding into voids in the arches, leading to major weakening of the structure. Three or four years ago, the leat was diverted away, permitting the arches to 'dry out'.
I don't know the present state of play, but I believe that grants were applied for to make good the structure.
By the way, there is one other railway site in Cornwall on the HE At Risk register: St Blazey turntable. Here, though, I gather that the news is good.
Driver Alan Peters
Views from 'on high'