It appears not to be large lumps of coal in the wagons (including two of the ‘French’ mineral wagons with cupboard doors), I think it is some kind of rock or ore working back towards the Midland main line. If it had been coal it is working 'the wrong way' it must have come down the ECML (or even to Cambridge) and then was being worked back to Bedford. I would have expected coal for there to have simply come down the Midland main line.