Passing times at Cardiff Central:
7E87 Briton Ferry - Immingham @ 1855 - the previously mentioned anthracite working.
6M45 Waterston - Glazebrook @ 2148 - loaded Oil tanks
6M14 Abercwmboi - Ellesmere Port @ 2320 - containerised household coal in FPA wagons I believe.
Pengam / Tidal area:
6B11 West Ruislip - Tidal arrival 0108 - unspecified metals working
6A10 1440 Tidal - West Ruislip - unspecified metals working
4S81 1830 Pengam - Coatbridge - freightliner
A bit more to go on there