Types of points

Discuss the prototype and how to model it.
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Types of points

Postby RAO » Wed Dec 12, 2018 6:01 pm

Can anyone advise the differences between type A, B, C and D points other than dimensions?

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jim s-w
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Re: Types of points

Postby jim s-w » Wed Dec 12, 2018 7:04 pm

Basically the letters A, B, C, D refer to the planing length of the switch blades.

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Re: Types of points

Postby grovenor-2685 » Wed Dec 12, 2018 7:11 pm

The difference is in the dimensions.
However that difference results in different allowable maximum speeds over the diverging track, the speed increasing with increasing radius which relates to the switch designation.
A switches are the smallest radius and hence lowest speed, of use only in shunting yards and similar.
B can be used in cramped locations with a speed limit around 15 mph
C and D are fairly common values for main line track
E and F can be used for higher speed junctions, approx 60 and 75 mph respectively
G, H and J come int use for really high speeds.
Full data can be had from the Network Rail track handbooks.
Info on the older GWR and BR(W) is available here http://www.norgrove.me.uk/permanent_way_notes.htm

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Re: Types of points

Postby jschybalski » Thu Dec 13, 2018 1:08 pm

The attached file is a table for CEN56 turnouts taken from the NR Track Design Handbook. CEN56 is still commonly referred to as 113 lb by some of us older folk and is one of the common modern flatbottomed rail types. The other is NR60 which is even heavier and is used on lines with higher speeds/lots of traffic. Many turnouts these days are DV, EV and FV switches - the higher speed turnouts are much rarer but do exist. For instance Aynho Junction is 90 mph throughout.

Turnout types.docx
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