turnout radius

[mitzimoonbeam]

Could anyone tell me which turnout equates to 5ft radius, I think a b6 is 4ft 6in so it is going to be a b8 or
b9?
Thanks
Phillip

[craig_whilding]

An 8 is 2452mm or about 8feet according to the Exactoscale template.

I think you'd be looking at a 1 in 6 1/2 looking at a table of crossings with B switches as that gives a radii for the turnout curve of 374feet. This table corresponds with the Exactoscale value too for the 1 in 8 with B switches at 613feet.

Don't forget the curve through the B switches is always 613 feet.

Source: LMR 95 LBS R.B.S. Switches and Crossings Chief Civil Engineer's Office Euston.

[Alan Turner]

If by 5ft radius you mean the internal geometric radius that approximately equates to a B6.25.

Alan

[steamraiser]

Playing with Templot a B 6.75 = 59.4 inches radius.

Gordon A
Bristol

[craig_whilding]

Which company are you modelling by the way? All of their standard leads varied slightly in length and radii too.

The radii I quoted was through the crossing.

The GWR for example quotes 371' for a 1 6 1/2 rather than the 374' of the LMR. http://www.norgrove.me.uk/GWRtracknotes/R1756.pdf

I think 1/4s were phased out more by BR where possible and it becomes a bit academic in 4mm trying to do that accurately anyway.

[mitzimoonbeam]

Thanks for the replies, i am no track expert , but I am trying to base the trackwork on the GWR, still working out how to put the joggle in the stock rails (is it worthwhile) 3/8" scaled down is not a lot.
It looks like a 6.5 angle will suit my requirements so I will give that a go.
Thanks
Phillip

[Alan Turner]

Playing with Templot a B 6.75 = 59.4 inches radius.

Gordon A
Bristol

For a B6.75 (P4) the internal geometric radius is 68.29" and the substitution radius is 93.53". So it all depends what you mean by turnout radius.

Alan

[grovenor-2685]

Try reading the other "new posts"
That topic has been under discussion this very day.
http://www.scalefour.org/forum/viewtopic.php?f=39&t=1618#p13084

Regards
Keith

[craig_whilding]

I was using the radii as covered here:

craigwelsh-Particulars_of_Switches_and_crossings.jpg

What was the reason for the 5' requirement btw, is it a minimum radii for something?