 Fast / Slow Line Layout
<rob499@m> wrote in message
news:8081db85-a836-43ca-afc5-a584d9640671@k30g2000hse..com...
On 17 Jul, 14:28, Sam Wilson <Sam.Wil...@ed.ac.uk> wrote:
> In article <431247c04f%R...@greywall.>,
> Graeme Wall <R...@greywall.> wrote:
>
> > In message <tmr88jrp7n00.yzx4cobed7a4....@40tude.net>
> > Chris Tolley <cj...@supanet.com> wrote:
>
> > > IRL, of course, things are rarely as black and white as that, so the
> > > layout will be designed to optimise the number of conflicting
> > > movements,
> > > which is one reason why rail layouts are sometimes redesigned when
> > > service patterns change.
>
> > While I'm sure we all suspect there are layouts specifically designed to
> > optimise conflicting movements the intention is usually to minimise them
> > :-)
>
> The pedant in me has to point out that "optimise" does not necessarily
> mean "maximise"... :-)
>
> Sam
>What nobody has pointed out yet is that when a main line is built as a
>2-track railway and then widened to a 4-track (as happened on the
>Great Western, for example), pairing by use is much easier than
>pairing by direction.
Well, it's certainly much cheaper - and usually nastier. Also, we tend these
days to think in terms of passenger traffic but many of the dedicated slow
lines (the Midland south of Wellingborough springs to mind) were almost
completely self-contained freight railways, where pairing by use did make
sense.
But I still think in modern conditions pairing by direction makes more
sense - who would build a motorway with DS, US, DF, UF? The southern part of
the WCML has now missed two chances to put its layout right - particularly
in the 1960s. Yes, it would need a flyover for the Northampton line, of
course.
Regards
Jonathan
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