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This is an additional circuit kit for our a Helix Starter kit and is suitable for OO gauge British Outline 3rd and 4th radius curved track (Peco, Hornby or Bachmann)and has a track bed 135mm wide.  It can follow the starter kit in being built either rising clockwise or anticlockwise.

Our Helix kits are laser cut from 6mm thick Lightweight Poplar ply, not MDF.  Poplar ply being a lot more stable and longer lasting than other substrates.  All joints are fully supported.

The circuit kit is to give you an additional 90 degree curve (1/4 of a turn) in the Helix

The Inner circuit based on 3rd Radius curves of 505mm has a gradient of 1 in 39 / 2.5%

The outer circuit based on 4th Radius curves of 571mm has a gradient of 1 in 44 / 2.2%

This pack comes with the following:

2x  1/8 circle sections.

2x  Connecting bridges including 2x inner segment guides, and  2x outer segment guides, 

All required nuts and washers 


You will need our  HO/OO 3rd & 4th Radius Curve Starter Kit and basic tools (a drill, 2x 13mm spanners, spirit level) and wood glue.

If you require an additional 180 degree curve (1/2 of a turn) please order 2 of these


Other bespoke Radii are available to order please contact us for a quotation. 


Please Note:

All Helices are made to order and will take 2 weeks to produce.

No Baseboards are included, they are available to special order, please contact us for more info.



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90 Degree extension for HO/OO 3rd & 4th Radius Curve Helix

£15.95 inc. VAT
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