As Eloise says, it is rare to actually time(table) trains at successive locations close by. The Camden example quoted is one where there are two distinct junctions in close proximity, in a dense area where freight, fast passenger, and slow passenger services all meet.
When producing the Sectional Running Times (SRTs) the computer will produce point-to-point times down to the second, and some element of common sense and judgment is then overlaid to produce the SRTs used by the Timetable Planners. For example, you need to balance out rounding down and rounding up to the nearest half minute over a sensible distance, rather than simply applying mathematics to it.
Returning to the original thread, the most spectacular examples are when you have high speed services passing at speed through densely populated residential areas (i.e.those with frequent commuter stations). I'd discount those stations where the fast trains merely pass by on a middle (non-platform) road. So most of Euston - Watford would be out, but Kings Cross to Potters Bar and Paddington to Didcot might throw up some good contenders. New Barnet to Oakleigh Park maybe?
www.realtimetrains.co.uk
