Minimum radius question.

[John Hubbard]

Apologies if this is repeating an existing thread, I've looked but can't find it.

 

At the club we are in debate concerning a proposed new layout and one of the contenders is  a dock layout. 

Given your expertise could you share your advice with regard to minimum radius that a MODEL can negotiate in either OO (or my pref' EM)?

We're expecting to be using short wheelbase 0-4-0, with 4 wheel wagons, and I'm wondering is we can go tighter that Peco setrack radius and if so by how much, and any advice you can share if we follow this route, e.g. catch rails etc.  BTW we're expecting to make track rather than buy.

[decauville1126]

This question comes up quite often. Basically it's not just radius but also couplings, buffer locking, and overhang to consider. I've done 3" radius in P4 as an experiment and a Tenshodo/Hanazono WB24.5 rewheeled spud worked fine. Four link couplings and short wheelbase wagons with pivotal w-irons also helped. But propelling produces other aspects such as buffer locking and flange climbing.

 

I've always suggested to others that a trial with some gash yards of flexitrack will give you far more physical answers than theoretical thoughts.

[Andy Reichert]

https://www.youtube.com/watch?v=-FwowQZ_kR0

 

I've made 8" radius work for dock style inset track

 

Andy

[John Hubbard]

Thank you for your thoughts.  The flex track experiment option makes a lot of sense, as do the cautions.

 

 

[Barclay]

0-4-0 loco's and 4 wheel wagons can traverse very tight curves, but the limiting factor is probably couplings. I use 3-link and keep to mostly 3' or so, but this one siding starts as a 3' radius point and sharpens down to about 12"-15". It does work but the couplings will have none of it even with sprung buffers. I have to uncouple to push a wagon in and 'imagine' some sort of cable shunting when a wagon is extracted from it. 

 

[PatB]

As an aside, I've mentioned before that I paced out a 90 curve at Gloucester docks and, after doing the scale conversion, found that it was pretty much bang on R1. Full size it looked pretty tight. 

[Regularity]

Most prototype wagons until modern days would traverse a 1.5 chain (=99’) radius curve with ease, which is 396mm, and first radius is 371mm, with second radius at 438mm.

Given the extra clearances in 00 compared to the prototype, first radius should be ok.

[crackedmember]

I believe that Fleischman used to make a 10" radius curve (H0), for use in sidings or industrial lines. 

Some of their bogie vehicles go round tight curves better than the longer 4 wheelers.  I do not know whether their six wheel coaches would, but these have genuine cleminson type flexible chassis so might.  These six wheel  chassis may be useful as the basis for some special wagons?

 

 

 

 

[Joseph_Pestell]

3 hours ago, crackedmember said:

I believe that Fleischman used to make a 10" radius curve (H0), for use in sidings or industrial lines. 

Some of their bogie vehicles go round tight curves better than the longer 4 wheelers.  I do not know whether their six wheel coaches would, but these have genuine cleminson type flexible chassis so might.  These six wheel  chassis may be useful as the basis for some special wagons?

 

 

 

 

Roco did some curves of about 10" radius as well although I think that these were intended for tramcar models.

[Peckett 560]

I used an 0-4-0 engine and a 4 wheel wagon on a 358 mm radius (Roco R2) for testing reasons. Both models (00) are fitted with 3 link couplings and perfomed very nicely. No buffer locking or flange climbing.

[5050]

On my 'Braynerts Sidings' layout in P4 I copied some Setrack points geometry and, with short 4 coupled and short wheelbase 6-coupled industrial locos and 4 wheel wagons with 3-link couplings it seems to work.

 

However, due to exhibition cancellations it has never been tested in anger yet!