I would say that the photo is about 1875. Mixed gauge arrived at Redruth in 1866, but the rails look more modern, with cross-sleepered track, so later than 1866, I reckon. The wooden viaduct is still there, so before 1888. The down side sidings went in 1914.
The cottages on the right are 'Jacks Platt' a- well-known Redruth slum area, finally demolished by nazi bombers in WW2. The post office (1957) occupies the site today.
All the best, Roy. Many thanks Roy.