The 13:21 working from Whatley to Dagenham seems to carry a particularly dusty grade of limestone, prone to being spread across the countryside if it gets caught by the wind. 59004 took the Westbury line at Fairwood Junction with 6L21 on 23 April 2021.
PHOTO DATA FOR IMAGE 21-D-0875
camera : Nikon D600
lens : 70-200mm f/2.8
focal length : 75.0 mm
shutter : 1/800 sec
aperture : f/8.0
ISO : 180 ISO
original : Digital: 24MP NEF
SUBJECT DATA
Loco / Unit : 59.004
Train : 6L21, 13:23 Whatley Quarry - Dagenham Dock A.R.C. stone