Archie Atkinson
Active Member
I am awaiting,in anticipation, of the forthcoming MOK 9f. Would a B8 point be the minimum I could use in S7?
Minimum Radius
- Thread starter Archie Atkinson
- Start date
Tim Humphreys ex Mudhen
Western Thunderer
Archie (John?)
The 9f was built to negotiate 4 1/2 chains, 99 yard radius curves. That's near enough 7 feet radius. I believe a B8 equates to something like a 13 foot radius so there is probably room to use a tighter radius turnout. Loco yards seem to have very tight radii turnouts, perhaps someone has information on these.
Tim
The 9f was built to negotiate 4 1/2 chains, 99 yard radius curves. That's near enough 7 feet radius. I believe a B8 equates to something like a 13 foot radius so there is probably room to use a tighter radius turnout. Loco yards seem to have very tight radii turnouts, perhaps someone has information on these.
Tim
Eastsidepilot
Western Thunderer
An A6 would equate to just greater than 4 1/2 chains so this would be the minimum turnout you could use prototypicaly.
I have all the info/dimensions available, not at this precise moment, but can supply them later if needed.
Also remember gauge widening on plain track under ten chains.
Col.
I have all the info/dimensions available, not at this precise moment, but can supply them later if needed.
Also remember gauge widening on plain track under ten chains.
Col.
Dog Star
Western Thunderer
A 4 1/2 chain radius curve in 7mm scale is 6' 9" approximately, or just under 2100 mm in foreign folding stuff.
The S7 Starter Pack includes data tables of Bullhead REA switches / leads... and column "R" is the radius through the diverging lead, my reading of the table is that, for example, a LNER A6 has a curvature of greater than 2100mm so a 9F ought to run through at dead slow. A B6 is of similar curvature. The tables cover all of the post-group companies.
If you do wish to put a 9F through such tight turnouts then consider including progressive gauge widening for the closure rails (start at +5 thou, then +10 thou, then +15 thou over six or seven timbers... at each end of the closure rail).
[this post editted to add that the data tables in the S7 Starter Pack include switch and lead information for all of the grouping companies.]
The S7 Starter Pack includes data tables of Bullhead REA switches / leads... and column "R" is the radius through the diverging lead, my reading of the table is that, for example, a LNER A6 has a curvature of greater than 2100mm so a 9F ought to run through at dead slow. A B6 is of similar curvature. The tables cover all of the post-group companies.
If you do wish to put a 9F through such tight turnouts then consider including progressive gauge widening for the closure rails (start at +5 thou, then +10 thou, then +15 thou over six or seven timbers... at each end of the closure rail).
[this post editted to add that the data tables in the S7 Starter Pack include switch and lead information for all of the grouping companies.]
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[The S7 Starter Pack includes data tables of Bullhead REA switches / leads... and column "R" is the radius through the diverging lead, my reading of the table is that a LNER A6 has a curvature of greater than 2100mm so a 9F ought to run through at dead slow. A B6 is of similar curvature.]
Graham
It doesn't only apply to LNER as post 1926 LMS and SR also used the same RCH standards for new trackwork; the GWR only maintained their own standards. I have had access to the 1926 SR S&C crossing diagrams and these compare exactly with LNER standards at the same period.
Rob
Graham
It doesn't only apply to LNER as post 1926 LMS and SR also used the same RCH standards for new trackwork; the GWR only maintained their own standards. I have had access to the 1926 SR S&C crossing diagrams and these compare exactly with LNER standards at the same period.
Rob
Eastsidepilot
Western Thunderer
The 9F also had a flangeless tyre on the centre axle I believe, obviously to help on tighter radius track and there may have been a certain amount of side play on the axles ( I don't know for sure) which you can build into your model.
Col.
Col.
Archie Atkinson
Active Member
If you are at Brightwell next month we shall have a chat....John