SR 4 COR No 3124 passing Clapham Junction on 16 July 1964. Robert Waterman adds "The other unit to which 3124 is coupled is 3148 in a mirror image formation to 3124 with the another ex 6PUL motor coach as the rearmost vehicle and 4COR motor coaches in the middle. When I saw it at this time the two units it seemed always to be used in the 8 car formation depicted here on a Farnham Monday - Friday rush hour service. On summer Saturdays another 4COR was added to the front or back (I can't remember which) and used as one of the extra Portsmouth Harbour services. These formations did not last long and reverted to standard 4COR units after a fairly short time. I never did discover the reason for the substitution of one ex 6PUL motor coach per set. Whether it was to test the performance/timing benefits or not of a 50% increase in power on the Portsmouth direct I don't know."
