The inbound working was from West Ealing which suggests a 387, although why would that need dragging to North Pole?
There's an earlier cancelled move from West Ealing sidings to Reading which would have been a loco hauled move.
Perhaps something has changed at quite short notice, and if the
EMUs▸ had been specifically prepared for haulage by a loco, they may have just carried on using the loco.?
Paul