Jump to content
 

practical minimum radius question


aleopardstail
 Share

Recommended Posts


Hi, new to 2mmFS, I had been planning an N gauge layout, but desired to assemble my own point work for a range of reasons, it seemed that if going that far I may as well at least consider a finescale layout.

 

The layout calls for a reverse loop but is 24" deep - it could be extended slightly but not vastly, I'm aware that curves of 10" & 11" (ish) are visually not very good so such will mostly be hidden (or entirely hidden) at the ends, my question is how practical are such for 2mm finescale. (essentially roughly 2nd radius set track type curves)

 

the rolling stock planned is all 1970s/80s/90s diesel/electric locomotives (mostly twin and some triple axle bogie stock) plus bogie coaches so nothing with an excessive wheelbase and the curves will not be taken at any significant speed - note there will be zero pointwork on the curves - its just getting a twin parallel track to do a 180 degree turn on a 24" deep board (its going on a shelf).

 

its possible a gradual gradient will also feature on the curves but this could be designed out if its a complete "ahahahhhhahhaaaa no" point 

 

also aware that such curves will rule out any long wheelbase stuff (e.g. Class 40 are not expected to feature), coaches will be largely Mk1, possibly some Mk2 stock, not sure Mk3 would look right without the ability to run more than the planned four/five coaches and that there is essentially zero chance for any steam era locomotives to get around the corners - this not being a problem for me as I'm not planning on running any

 

I will be trying some experiments with this but if wiser heads have already tried it and know it doesn't work I can try a bit of a re-think.

 

many thanks :)

Link to post
Share on other sites

  • RMweb Premium

In general, I try to avoid less than 3 foot radius on scenic sections. Bogie diesels and coaches can usually handle 2 foot radius. Pushing it down to 12 inch radius would probably need some gauge widening and might restrict you Bo-Bo locomotives. You will also need lots of length on the couplings to avoid buffer locking, so close coupling of coaches is probably out of question.

 

As you say, experimentation is good, and you might find a way to achieve what you are wanting.

 

  • Like 1
  • Agree 1
Link to post
Share on other sites

7 minutes ago, Ian Morgan said:

In general, I try to avoid less than 3 foot radius on scenic sections. Bogie diesels and coaches can usually handle 2 foot radius. Pushing it down to 12 inch radius would probably need some gauge widening and might restrict you Bo-Bo locomotives. You will also need lots of length on the couplings to avoid buffer locking, so close coupling of coaches is probably out of question.

 

As you say, experimentation is good, and you might find a way to achieve what you are wanting.

 

 

Ok, experimentation it is, with possibly some other method of looping around needed, still experiments can't hurt.

 

Yes I did think close coupling would be out of the question, I can live with that if it means I actually get to play trains for the first time in over a decade and a half.

 

limited to twin axle bogies for locomotives would also me manageable, the only ones I have so far are a pair of ancient Lima Class 86 - which perhaps indicates a level of flexibility where accuracy is concerned here.

 

experiments and mad science ahead

Link to post
Share on other sites

Izzy, who posts on the forum reasonably frequently, has made a pretty tight radius roundy-roundy layout, and got it to work with bogie passenger stock.   His experience might be useful on how to handle such tight curves. 

 

The alternative is to consider a turntable in the space, but that assumes a train length of no more than 24 inches.  Which is a easy 3-coaches plus loco, but might be tight on four coaches plus loco.  

Link to post
Share on other sites

  • RMweb Premium

As Nigel has said I built a small roundy with curves down to 12” radius through about a 90 degree turn using 2FS gauge widened soldered track - just a single line - and had no issues. N gauge stock with their normal couplings coped with it quite okay. Most of my stock uses DG’s which can actually couple/uncouple on such radius. Farish 47/37/31/24/20 & a Dapol 66 went around okay as did 101/108/158 DMU’s. 
 

However I very much doubt double track at anything under this would be feasible and what stock could cope would only be determined by trying them.

 

Whilst I would not wish to deter you from using 2FS I do wonder if what you wish to achieve could be accomplished more easily using N standards. You can still hand build the track using 2mm association and FiNetrax parts, just you would have slightly more ‘wriggle’ room. 

 

  • Like 1
  • Agree 1
Link to post
Share on other sites

11 hours ago, Izzy said:

Whilst I would not wish to deter you from using 2FS I do wonder if what you wish to achieve could be accomplished more easily using N standards. You can still hand build the track using 2mm association and FiNetrax parts, just you would have slightly more ‘wriggle’ room. 

 

 

That's my thoughts as well for something where the stock is N and modern diesel/electric.  FiNetrax offer a lot of turnout kits.   

  • Agree 1
Link to post
Share on other sites

  • RMweb Premium
8 minutes ago, Nigelcliffe said:

 

That's my thoughts as well for something where the stock is N and modern diesel/electric.  FiNetrax offer a lot of turnout kits.   


Yes, and of course you can always use plain line easitrac for the tight curved bits to give a bit of automatic built-in gauge widening to help things along. I believe quite a few who have built to N gauge finescale have used easitrac throughout combined with either fiNetrax or hand built pointwork, Blueball Summit comes to mind.

  • Agree 1
Link to post
Share on other sites

  • RMweb Premium
21 hours ago, aleopardstail said:

Yes I did think close coupling would be out of the question, I can live with that if it means I actually get to play trains for the first time in over a decade and a half.

Not necessarily.

There is a great little article by John Whitehead in the December 1980 Magazine on his Expanda-Link close couplings.

He reports these will work down to 7" radius curves!

Link to post
Share on other sites

Another vote for Finetrax if you'll be using exclusively diesel / electric stock and/or commercial N models. I model in 2mm for my pre-grouping steam models, which would usually have to be kit built anyway, and where the wheels and connecting rods are more "obvious", but if I ever get around to building a layout for the sector-era BR models that I've collected, it will be Finetrax/hand-built N. Why go to all the effort and expense of changing all those wheels when they're mainly hidden behind bogie frames?

 

The Finetrax range is growing, and the straight turnouts etc can be curved using the techniques that Mick Simpson wrote up for the pegged version of 2mm Easitrac turnout kits (which are essentially identical to the Finetrax ones, apart from the gauge). Indeed, you can get beautiful kits for concrete turnouts in Finetrax that aren't available in 2mm!

 

As well as Blueball Summit, TomE's Ropley comes to mind as an excellent example of hand-built N track using 2mm components. 

 

On radius I would also echo the comments on couplings being key. If you could rely on everything having effective close coupling mechanisms then you'd probably be fine, but alas even some brand new models like the Farish Mk2 air-cons don't have close coupling, so could prove to be a problem.

Edited by justin1985
Link to post
Share on other sites

Hi, many thanks and much to think about.

 

"Da plan" was to use a 10'x2' sheft in the backroom/office/mess/junkyard above the main work desk (when either get built), hence the width restriction. It started out as something with a train turntable but not sure I could get it working right so wanted a more conventional out & back, looping round and under then back.

 

There is an alternative location which is a cellar, where the same basic station can be managed, through to a storage yard of run round roads (no loop), in theory the station gets about a foot shorter but it wasn't using the full length anyway so managable, can then have two fixed bits and a removable curve between them closer to 36" which should work (having run 48" curves in N in a previous house and found it hard to tell they were actually on a curve I suspect this will work)

 

The concept was "N", I wanted to make my own pointwork, I did consider FiiNetrax, but figured if I was going to the effort anyway 2mmFS would likely look better and I gather more modern stuff isn't too hard to convert.

 

my last attempt at close coupling was a rake of N gauge Lima Mk1 coaches, run as a rake, sadly don't have them but was done by taking the front bit off the couplers to leave the spring and the rubbing plate, then a wire loop round them - bit of concertina folded black paper for a connection, avoid looking too closely and it worked

 

the terrible paint job was a distraction...

 

 

Will soon have an "N" test loop for checking things work while I plan some smaller test track and start measuring the cellar :)

Link to post
Share on other sites

35 minutes ago, aleopardstail said:

 

The concept was "N", I wanted to make my own pointwork, I did consider FiiNetrax, but figured if I was going to the effort anyway 2mmFS would likely look better and I gather more modern stuff isn't too hard to convert.

 

It isn't hard to convert, until you trip over the "tricky one".   But each conversion costs some time and money. Unless you get really drastic in conversions, the outside of the bogies don't move.  

 

I think the only real difference is found when looking along track from the ends, then the tighter crossings gaps and checkrail clearances of 2mm do look better than N.   But, across the rails from the side, I'd suggest few would spot the difference if using Finetrax.  And, choice of "correct" track type (concrete sleeper, flatbottom rail), plus time spent on track-side stuff (point rodding, motors, locking gear, electrical conduits, etc.) is much more distinctive.   

 

 

If asking about scale track, I wouldn't worry about the Lima carriages.  Like much N of the period, they were random scale.   

 

 

- Nigel

  • Agree 1
Link to post
Share on other sites

  • 7 months later...
On 22/03/2021 at 12:48, justin1985 said:

Another vote for Finetrax if you'll be using exclusively diesel / electric stock and/or commercial N models. I model in 2mm for my pre-grouping steam models, which would usually have to be kit built anyway, and where the wheels and connecting rods are more "obvious", but if I ever get around to building a layout for the sector-era BR models that I've collected, it will be Finetrax/hand-built N. Why go to all the effort and expense of changing all those wheels when they're mainly hidden behind bogie frames?

 

The Finetrax range is growing, and the straight turnouts etc can be curved using the techniques that Mick Simpson wrote up for the pegged version of 2mm Easitrac turnout kits (which are essentially identical to the Finetrax ones, apart from the gauge). Indeed, you can get beautiful kits for concrete turnouts in Finetrax that aren't available in 2mm!

 

As well as Blueball Summit, TomE's Ropley comes to mind as an excellent example of hand-built N track using 2mm components. 

 

On radius I would also echo the comments on couplings being key. If you could rely on everything having effective close coupling mechanisms then you'd probably be fine, but alas even some brand new models like the Farish Mk2 air-cons don't have close coupling, so could prove to be a problem.

Does anyone know if the description of curving easytrac turnouts is available anywhere?  It's something I've wondered about and would be very interested to know more details of someone who has already done it.

Link to post
Share on other sites

On 21/11/2021 at 23:03, Coder Tim said:

Does anyone know if the description of curving easytrac turnouts is available anywhere?  It's something I've wondered about and would be very interested to know more details of someone who has already done it.

 

I've just looked this up, and I must have been mistaken in my previous post. It wasn't Mick Simpson who wrote up the curving technique at all. The relevant articles are by Geoff Jones, 'Curved turnouts for pegged chairs' in the June 2016 2mm Magazine, and by Rod McCall in the August 2016 issue.

 

Basically Geoff's method is to cut out a large part of the web between sleepers on the outside of the curve, on between alternating pairs of sleepers (i.e. solid web, sleeper, web cut away to centre line, sleeper, solid web ... )

 

Rod's method perhaps a bit simpler - simply cutting a single cut almost all of the way from outside to inside of curve in the web between alternating pairs of sleepers. (i.e. leaving most of the web in place, just cutting but leave a tab to keep everything intact)

 

This blog from the 2mm Kent and Essex Area Group illustrates the two methods pretty well https://2mmkeag.blogspot.com/2021/06/june-2021-meeting.html 

 

I don't see any reason why this method wouldn't work with Finetrax as well?

Link to post
Share on other sites

On 25/11/2021 at 10:31, justin1985 said:

 

I've just looked this up, and I must have been mistaken in my previous post. It wasn't Mick Simpson who wrote up the curving technique at all. The relevant articles are by Geoff Jones, 'Curved turnouts for pegged chairs' in the June 2016 2mm Magazine, and by Rod McCall in the August 2016 issue.

 

Basically Geoff's method is to cut out a large part of the web between sleepers on the outside of the curve, on between alternating pairs of sleepers (i.e. solid web, sleeper, web cut away to centre line, sleeper, solid web ... )

 

Rod's method perhaps a bit simpler - simply cutting a single cut almost all of the way from outside to inside of curve in the web between alternating pairs of sleepers. (i.e. leaving most of the web in place, just cutting but leave a tab to keep everything intact)

 

This blog from the 2mm Kent and Essex Area Group illustrates the two methods pretty well https://2mmkeag.blogspot.com/2021/06/june-2021-meeting.html 

 

I don't see any reason why this method wouldn't work with Finetrax as well?

That's brilliant, thank you, will definitely be giving it a go

Link to post
Share on other sites

  • RMweb Premium

I've put a very subtle curve into Finetrax turnouts without any modifications, but yes, I'm sure that cutting the webbing would allow some more extensive curvature, the bases are not particularly rigid!

 

I realise this is quite an old thread now too, but I'm also combining Finetrax with Easitrac plain track, seems to work alright based on my glacial progress so far! Would seem a better solution for the OP.

Link to post
Share on other sites

Perhaps slightly off-message but I have managed to turn a Peco code 55 large radius turnout into a mimic of a Peco curved turnout by cutting through webs between alternate sleepers. Obviously more subtle changes are possible.

John

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...