Dan Gravell wrote:
wrote:
I'd advocate six, but I think 8 is unrealistic - major stations aside
(East Croydon, Wimbledon etc) how many routes have 8tph?
Put simply - build them. You're right that few have 8tph, but the
setting of the waterline at four seems more a decision based on
marketing than it does the semantics of the word "frequent".
I think a 15 minute interval is just enough to qualify - after all,
given that the average wait should be 7.5mins, that's just enough time
at the big terminals to buy a ticket and find the platform if you're
unfamilar with the place.
4tph is also the off-peak frequency to London at Richmond, Ealing
Broadway (District) and Rickmansworth outwards. I accept that that's a
small proportion of stations.
It is interesting that 6tph is "standard" offpeak Tube frequency on
outer London Tube services like the Central line's West Ruislip branch
or the Piccadilly's Rayners Lane branch, whereas 4tph is deemed
sufficient on National Rail, even at inner London stations like
Loughborough Junction, Streatham Hill, Deptford and St Johns.
--
Dave Arquati
Imperial College, SW7
www.alwaystouchout.com - Transport projects in London