51877 Bramshall 12 August 1989

51877 leads the 14:47 Crewe to Derby service past Bramshall on 12 August 1989. There is a slight mystery here. 51877's number was noted at the time, and can be read off the original Fujichrome slide. However, the set number T405 should indicate that this would be 51854. The '05' of the set number does appear to be half obliterated. Information anyone?