northbound coal Saturday c.1430 60054 on 6F96.
FL coal through Nantwich, heading for Crewe c.1555 Monday - if you mean yesterday, there was 66415 on 4V58, but that passed through Nantwich 1645.... Did you mean approx 1655 rather than 1555?
Edit - the only other thing that was about and running through Nantwich around that time that I cn see was 6M64, which passed through Nantwich 1343, sat in Basford Hall Yard 1350 - 1530 (approx) then set off towards Winsford on the WCML - so it depends where you saw the freight? If that one fits, it was 66518 to Basford Hall, 66506 thereafter.