David J. Hayes comments "Based on some of the other images and comments, this looks very much like 1S31, the 19:19 MWSO Motorail service from Newhaven Harbour to Stirling, which was booked to call at Kenny-O (20:51-21:00) for a crew change and to attach traffic. It ran during the period 19th May to 27th September 1969 and was routed via Old Oak Common rather than joining the WCML.

As mentioned elsewhere, its routing from "Kenny-O" was by way of Old Oak East Junction-Park Royal-South Greenford-West Ealing-Acton Main Line-Acton Wells Junction and Brent Curve Junction where it joined the Midland Main Line for its northward departure from London".