A beginner's 00-SF, and the ends of wing and check rails

[47137]

I am embarking on making four more points from flat-bottom rail for my new layout. When I look at photos of point work built from bullhead rail, I see the ends of the check rails bent away at a slight angle. This applies to both the real thing and models. But looking at photos of modern point work built from flat bottom rail, the prototype seems to use straight rails ground down to a slight taper on the inside.

 

Is there a basic rule of thumb here - for example, because full-size FB rail is too difficult to bend?

 

My thinking is (for a model of no particular prototype), it is easier to bend model rail than to grind it down. However, a straight FB rail with a taper on it should draw less attention to the too-narrow 00 gauge - at least if I do it right

 

- Richard.

[martin_wynne]

Hi Richard,

 

Nowadays most heavy-rail FB in the UK uses machined flare angles on straight check and wing rails. This is mainly to allow for different lengths of flare angle (according to line speed) without the need for special baseplates. (Making a bend isn't too difficult, as for the knuckle bends in the wing rails).

 

Lighter FB rail, such as on industrial and light railways, normally has bent flare angles because it is much less expensive to make.

 

But it all It depends on the prototype -- here is some Irish heavy FB rail with bent flares:

 

 

Templot has an option to switch between bent or machined flares, individually for each rail.

 

Martin.

[47137]

The rail is Peco code 75, to match their 00/HO track. I'm not sure if this is "heavy" rail but if it is borderline then I'll assume it is HO scale i.e. worst case. The first point to build is a left-hand point with a negative radius of about 900 mm, this needs a space on the layout somewhere between that needed by the Peco small and large radius 00/HO Wye points. The crossing angle is 1:3.5 and the plot is set up for 00-SF. I am thinking, the check rails for such a construction would most likely be bent not planed?

 

- Richard.

 

 

[jonny777]

Hi Richard,

 

Nowadays most heavy-rail FB in the UK uses machined flare angles on straight check and wing rails. This is mainly to allow for different lengths of flare angle (according to line speed) without the need for special baseplates. (Making a bend isn't too difficult, as for the knuckle bends in the wing rails).

 

Lighter FB rail, such as on industrial and light railways, normally has bent flare angles because it is much less expensive to make.

 

But it all It depends on the prototype -- here is some Irish heavy FB rail with bent flares:

 

 

Templot has an option to switch between bent or machined flares, individually for each rail.

 

Martin.

 

 

 

That sleeper spacing looks almost to be Peco closeness, or is it a trick of the camera?

[47137]

I think, the spacing of both my plot and Martin's example are close to Peco spacing. This would fit into my model quite nicely - I have gapped out the Peco sleepers on the plain track and I'd expect the crossing timbers to be closer together, i.e. closer to the Peco norm.

 

- Richard.

[jonny777]

Yes, I suppose the main variable is the turnout radius.

 

In my case, while I would love to have large radius pointwork throughout the visible area, in practice this becomes impossible due to the space they take up.

 

Oh for a 50ft x 30ft free attic space.

[martin_wynne]

That sleeper spacing looks almost to be Peco closeness, or is it a trick of the camera?

 

Hi Jonny,

 

I think it may be the visual effect of the 5ft-3in Irish track gauge.

 

regards,

 

Martin.

[martin_wynne]

The rail is Peco code 75, to match their 00/HO track. I'm not sure if this is "heavy" rail but if it is borderline then I'll assume it is HO scale i.e. worst case. The first point to build is a left-hand point with a negative radius of about 900 mm, this needs a space on the layout somewhere between that needed by the Peco small and large radius 00/HO Wye points. The crossing angle is 1:3.5 and the plot is set up for 00-SF. I am thinking, the check rails for such a construction would most likely be bent not planed?

 

Hi Richard,

 

Peco code 75 FB rail is underscale for 00 gauge (4mm/ft scale). It should be Code 82 to be the correct height.

 

Usually the choice of check rail flare would be based on the prototype. If this is a light railway or industrial private siding, etc., use bent flares. If it is intended to represent ordinary BR FB track, use machined flares.

 

Peco turnouts have silly short plastic check rails with machined flares.

 

p.s. important -- is that turnout leading to a siding or branch track? If so you need to change it to a curviform type V-crossing in Templot. If it is part of a crossover, it is ok as it is, set for a regular type V-crossing.

 

See : http://templot.com/martweb/gs_realtrack.htm#xing_types

 

And: http://templot.com/martweb/tut5e.htm Sorry that page is so old.

 

regards,

 

Martin.

[47137]

Well, 75 is about 88% of 82, so the difference makes sense for an 00 main line. I'd like to think, 75 (or even the 64 from Peco code 60) is reasonable for a light railway or industrial line, and I've settled on 75. Though I quite like the look of the narrower foot of Peco code 80 applied to 00 track. My layout will be of an industrial line, so the points can have bent flares - good.

 

Really, I suppose, that answers my original question. However I am very happy for this topic to digress onto "making a scale point which is quite close to a Peco one"! I designed the layout with AnyRail and set out the cork underlay for Peco, and while I can alter the cork I don't have a great deal of space to play with.

 

For check rails I think we have got to bear in mind that Peco points are designed to look passable for a huge variety of applications. Looking at one of their small radius points, the check rails look too short to me - they finish short of the wing rails - but if they were longer and "correct", they would make the whole assembly look like something from an industrial siding. A lot of purchasers will want to use small radius points for "main lines" in tight locations, and as they stand the Peco points are reasonably anonymous things which don't draw attention to themselves.

 

My turnout is leading to a siding. Changing the design to use a curviform crossing makes the whole thing a quarter inch or so shorter and a rather better fit to the cork underlay - good.

 

Thank you for all of the advice.

 

- Richard.

 

[47137]

I've had a gentle Sunday morning - see pictures below. The thing is wanted to blend in with Peco track so the arrangement of the timbers is rather different to the template from Templot. I'll trim the overlength ends when it comes off the template.

 

RTR 00 runs ok through the gentle side, but I had to ease the check rail quite visibly to persuade it to go through the 'siding' side (third photo below). I also ground some metal off the inside of the adjacent wing rail but this doesn't show up in the photos very well. The smaller radius is about 24 inches (seen by putting a 24" Tracksetta on top) so I guess the minimum radius for 00-SF is around 30 inches. So the next attempt has got to be more gentle, or maybe I'll have to go back to 00-BF.

 

I'm not so sure about the "goodness" of the curviform crossing - yes it may be more prototypical but it's even harder to make and I'm not sure if anyone will ever see the difference.

 

This is actually my first completely hand-made point, all of my others have been from kits or have taken bits of rail rail from stripped down Peco. Quite pleased so far but the real proof will be in seeing a loco go through it and I have some doubts about the siding side.

 

- Richard.

 

[martin_wynne]

Hi Richard,

 

Well done, but yes, 00-SF needs gauge-widening below about 30" radius -- did you use the 3-point track gauges? Or you could use 16.5mm roller gauges on 24" or below.

 

You shouldn't need to adjust the check rails if the wheels back-to-back is correct (14.4mm for RTR). If you do adjust them you may get derailments on the crossing. The check gauge for 00-SF and 00-BF is the same. How well does the Peco rail fit in the check gauges? You did use the 00-SF check gauges and NOT set the check rail gap with a 1.0mm shim? It is for the wing rail flangeways only alongside the vee.

 

It is a good idea when building critical pointwork to fit the check rails first before adding the outer running rails.

 

I'm not convinced about the extended check rails. If you want inset track in the siding, the check and wing rails would usually be the normal length, and then further rails added in the siding after a short gap (unless the inset portion includes the turnout).

 

Don't change from a curviform crossing, otherwise the exit track will be curving the wrong way. If the divergence is too sharp, use the CTRL+F12 mouse action to shorten it to the minimum, extend the siding back towards the crossing, and then ease its radius.

 

If this is your first handbuilt turnout, you have made things extra difficult for yourself by using flat-bottom rail, and building such a short turnout on a tight curve. If other handbuilding beginners are reading this, it really is better not to jump in the deep end like this. Use bullhead rail, and build a simple straight turnout, say B-6 or B-7.

 

It would be better to forget Peco track entirely if you are handbuilding track. The prototype is a much better guide than Peco.

 

regards,

 

Martin.

[47137]

Thank you Martin for all of your comments. Especially, I would not recommend a 1:3.5 crossing to anyone for a first attempt! However I wanted something to fit into the place of a RTR turnout. If it didn't work out I had this to hand as a fall back.

 

I have now spent an hour+ making the thing work, and now it does. Actually I got the crossing area almost spot on but the point blades were too straight, so the track gauge here was too small, and the loco wanted to climb up them.

 

I didn't find the FB rail especially difficult to use - if I am allowed to mention Peco one more time, I copied what they do and cut notches in the foot to make sure the wing rails bent cleanly. I also filed and ground an awful lot of material off the bottoms of the switch blades, and next time I'd remove even more.

 

I used two gauges - a 15.2mm check gauge from C&L, which they market for 00-SF (but which as you say suits 00-BF as well) and a 00-BF roller gauge for the points end. The rail fits these nicely, not obvious slop. I've been too tight-fisted so far to buy a three-point gauge. I only want to make up a few points - but I take your point.

 

I'm not sure about your comment about putting in the check rails before the running rails. As a model, it works fine without any check rails. So why not put them in at the end? The important thing to my mind is to make the crossing spot-on. If the gauge has got to be widened to suit a tight curve, then surely it is best to get this all soldered up and working, and put in the check rails last. If they end up with 1.5 mm gaps because of the gauge widening, so be it - this is the price to be paid.

 

I have a continuous check rail on the inner rail of the siding because of the tight curve. I thought it would be easier to do the infill if I extended the wing rail through to the inset track. I sounds as though I should finish off the wing rail with a bend, leave a gap and then start the new outer check rail. I might have a search around for prototype photos before cutting into it :-)

 

I suggest, to build a turnout to 00-SF standards from end to end is a very challenging task indeed. It's easier to ease out to 00-BF at the points end, and even then it takes a fair amount of work to get the blades to go far enough home against the stock rails.

 

I worked up the assembly to begin with with solder on every third or fourth timber and my big mistake was to solder up everything before taking it all off the template to test it. It would have been more sensible to leave the assembly on the template, run a loco, ease the rails as need be and then solder it all up.

 

This is my third handbuilt turnout, but the other two used bits salvaged from RTR ones. So this is my first all-homemade one. I think I deserve a beer, no more points today! I'm encouraged enough to try another one.

 

(edited to delete the spec of the next turnout to build - it won't fit the layout)

 

- Richard.

[martin_wynne]

 

If they end up with 1.5 mm gaps because of the gauge widening, so be it - this is the price to be paid.

 

 

Hi Richard,

 

That is not a price to be paid -- it is correct. The check rail gap widens by the same amount as the track gauge. Hence my point about not using the 1.0mm gauge shim for this. And if you put the check rails in first, you can't.

 

The crossing will not work without the check rails. This is a common misunderstanding. It might appear to do so most of the time, but not always. If you try propelling (pushing) a train of loose-coupled wagons through a crossing without check rails, at least one of them will climb up on the crossing and derail, and several of them will bump the vee nose. Especially if the crossing is in the outer rail of a curve. Correctly positioned check rails really are an essential part of a crossing, not an afterthought.

 

I'm glad you have got it working -- well done and enjoy the beer.

 

regards,

 

Martin.

[Peter Bedding]

Prior to the Grouping, the larger Pre-Group Companies each had their own designs and standards for Switches and Crossings (S&C). I had collected sufficient data by about 1994 to produce a set of drawings for the South Western Circle (copies for sale to members) for most of the known various generations of LSW S&C.

 

I would stress that, for reliable scratchbuilt working models, Martin's Templot should be first choice. But it may be helpful to Forum readers to see some of the prototype variations that might be found in the Circle Archive  and could still be found in out-of-the-way- locations until well after the end of WW2.

 

 

 

 

There are various facts to note. One of the first is that on the LSWR, only the Switches and Crossings had an "ideal" plan, and associated lead. (Defined by Drawing Office - firstly Waterloo and then Eastleigh). The exact detail of the intermediate timbering was defined case-by-case by the appropriate District Civil Engineer. This may seem odd to our CADCAM generation, but it worked in its day.

 

 

PB

[47137]

The exact detail of the intermediate timbering was defined case-by-case by the appropriate District Civil Engineer.

Sounds like a useful fall-back for anyone taking their pride and joy to an exhibition and having to endure that particular kind of punter for whom everything they have done is somehow "wrong".

 

- Richard.

[martin_wynne]

I would stress that, for reliable scratchbuilt working models, Martin's Templot should be first choice. But it may be helpful to Forum readers to see some of the prototype variations that might be found in the Circle Archive  and could still be found in out-of-the-way- locations until well after the end of WW2.

 

Hi Peter,

 

Just to add that it is not either/or. Templot defaults to REA bullhead, but your data can easily be used to create custom turnouts and complex formations in Templot. Thanks for posting the drawings.

 

regards,

 

Martin.

[martin_wynne]

Hmmmm.  A lot of good data here but I am not sure I actually saw an answer to the OP.

 

Hi JF,

 

I posted what I thought was an answer in the 2nd post, sorry if it wasn't enough info.

 

http://www.rmweb.co.uk/community/index.php?/topic/97424-the-ends-of-wing-rails-and-check-rails/&do=findComment&comment=1826864

 

Sorry, I have no dimensions (as guilty as everyone else!)

 

 

I can post some dimensions if needed, but it varies with the line speed and crossing angle. For 00 gauge the amount of flare needed may be more than the rail head width, resulting in the check rail coming to a knife edge, which looks odd. It depends on the actual flange thickness and back-to-back being used.

 

regards,

 

Martin.

[47137]

Hi Richard,

 

That is not a price to be paid -- it is correct. The check rail gap widens by the same amount as the track gauge. Hence my point about not using the 1.0mm gauge shim for this. And if you put the check rails in first, you can't.

I see a price paid in visual terms - as the check gap widens, you wonder why you bothered with 00-SF in the first place. So having built this and seen it work (36 + 24 inch, 1:3.5), I'd say 00-SF is an excellent idea for the crossings of turnouts with a radius of 30 inches or so upwards. For smaller radii, it may be more aesthetically pleasing to stick with 00-BF because this will let you have matching gaps for the wing rails and the check rails.

 

As far as the check rails ends go, I can see an aesthetic advantage in 00 gauge for ground tapers "if you can justify them", because the rails will stay parallel and you won't get the 'miniature gauge' look at the bends. I have found an example of a three-way point where the wing rail extended from one crossing to the next, and some North American track on an overhead railway where a wing rail extended to a diamond crossing. However these are very much the exception and my own arrangement can only stay if I add some more trackwork categories to my modellers' licence, to go along with selective compression and crazy curve radii and quite a lot of other things.

 

At the moment, the main thing to me is that it works. Two more photos of it with a coat of primer and the insulating gaps filled in and overpainted. If I can make three more to the same standard I'll be very happy. Thanks for all the advice and information.

 

- Richard.

 

[martin_wynne]

I'd say 00-SF is an excellent idea for the crossings of turnouts with a radius of 30 inches or so upwards. For smaller radii, it may be more aesthetically pleasing to stick with 00-BF because this will let you have matching gaps for the wing rails and the check rails.

 

Hi Richard,

 

If you are running only RTR then I would tend to agree with you -- 00-SF is a variant of EM ("EM minus 2") and you can't really expect to do any more with it than you would in EM. It is not intended for train-set curves. But if you are also running stock with kit wheels, then the narrower 1.0mm flangeway at the crossing will give much smoother running, regardless of how wide the check rail gap is.

 

 

I have found an example of a three-way point where the wing rail extended from one crossing to the next, and some North American track on an overhead railway where a wing rail extended to a diamond crossing.

 

This is called a "parallel-wing crossing" where a wing rail is extended to form a check rail. They are quite common.

 

However, the inside rails on inset track are NOT check rails. They are not there to serve any purpose in controlling the wheels. They are simply there to keep the infilling clear of the wheel flanges. Prototypically the gap is usually wider than the check rail gap, typically, 2" (the check rail gap is 1.3/4").

 

Consequently they wouldn't easily be connected to parallel-wing crossings, they would be separate rails.

 

Someone will now post a photo showing the exact opposite.

 

regards,

 

Martin.

[47137]

I suspect, some inside rails on inset track are check rails too, but this is a cosmetic issue (as are check rail ends!) on a model.

 

What I really want is a graph of minimum crossing flangeway gaps against curve radii. We have two end points: 1.3 mm for 18-inch curves and 1 mm for 36-inch curves. If the graph could have different plots for typical wheel treads and flanges, such as those of Markits, Bachmann, Hornby and Lima (and even Wrenn and Hornby Dublo), then this would be perfect.

 

Then I could build track I knew would work, without running what are, at best, hopefully-representative "test vehicles".

 

- Richard.

[martin_wynne]

Hi Richard,

 

Lima (and even Wrenn and Hornby Dublo).

 

00-SF is suitable only for modern RTR models having RP25/110 wheels set to 14.4mm back-to-back, and finer kit wheels.

 

It's not suitable for older RTR models with coarser wheels.

 

00-SF is a variant of EM, it's not an alternative to 00 train-set standards. Stick to 00-BF or Peco for those.

 

You don't need a graph.

 

For both 00-SF and 00-BF the check gauge is always 15.2mm.

 

For 00-SF the crossing flangeway gap is always 1.0mm.

 

For 00-BF the crossing flangeway gap is always 1.3mm.

 

The check rail gap is the difference between the check gauge (15.2mm) and the track gauge. Below about 30" radius the track gauge progressively increases from 16.2mm to 16.5mm at say 20" radius, so the check rail gap increases progressively by the same amount from 1.0mm to 1.3mm.

 

If you want to calculate it for radius R inches, I suggest using this:  Track gauge  =   16.2  + ( 30/R - 1 ) * 0.6 mm  (not valid outside the range R = 20" to 30" )

 

Here are some results from that:

 

Radius inches     Track gauge mm     Check rail gap mm

 

     30              16.20             1.00

     28              16.24             1.04

     26              16.29             1.09

     24              16.35             1.15 

     22              16.42             1.22

     20              16.50             1.30

 

For long wheelbase vehicles, you may want more widening, say below 42" radius:  Track gauge  =   16.2  + ( 42/R - 1 ) * 0.3 mm  (not valid outside the range R = 21" to 42" )

 

Here are some results from that:

 

Radius inches     Track gauge mm     Check rail gap mm

 

     42              16.20             1.00

     39              16.22             1.02

     36              16.25             1.05   

     33              16.28             1.08

     30              16.32             1.12

     27              16.37             1.17

     24              16.43             1.23 

     21              16.50             1.30

 

 

These tables illustrate why the multi-slot roller gauges which the trade love are so useless, as they don't allow any variation in the check rail gap. A proper set of gauge tools has separate check gauges and track gauges, as those for 00-SF available from C&L. 

 

I hesitate to post these notes again below for the 97th time on RMweb, but here we go:

 

A is the check gauge. It is the most critical dimension in pointwork. If this dimension is too small, wheels running from left to right can hit the nose of the vee and very likely derail, or at least bump. If this dimension is too large, the wheel backs will bind or jam on the check rail. To make sure it's correct, the check rail is set using check gauge tools. For 00-SF and 00-BF this dimension should be 15.2mm. You can use the same check gauge tools for both these standards (they are both running the same wheels).

B is the crossing flangeway gap. It's also important. If this dimension is too small, the wheel backs will bind or jam on the wing rail. If this dimension is too large, the gap in front of the nose of the vee will be too wide, and the wheels may drop into it with a bump. This gap is set using a small piece of metal shim called a crossing flangeway gauge shim. For 00-SF it should be 1.0mm thick. For 00-BF it should be 1.3mm thick.

C is the track gauge. It shouldn't be less than the specified dimension, but it can be wider. It is often widened on sharply curved track to ease the running of long-wheelbase vehicles. The track gauge is normally set using roller gauge tools, or alternatively using a 3-point gauge tool, which automatically widens the track gauge on sharp curves. For 00-SF this dimension shouldn't be less than 16.2mm. For 00-BF it is normally 16.5mm.

D is the check rail gap. The width of this gap doesn't matter a damn, providing it is wider than the wheel flanges. It's whatever you end up with after setting A and C correctly. But where the check rail is combined with a wing rail in complex formations (i.e. in parallel-wing V-crossings) it must be the same as B.

 

regards,

Martin.

[AndyID]

tables illustrate why the multi-slot roller gauges which the trade love are so useless

I've had a several of these for years. I consigned them to the trash a couple of weeks ago and made myself a set that comply with the SF spec.

 

Andy

[47137]

Martin's post earlier today is the best explanation I've read so far. I do think, someone looking for it in the future will not be searching under "the ends of check rails" and it would be well worthwhile to lop it out of this topic and pin it to the top of the forum under the heading of something like "moving from 00-BF to 00-SF". I started out reading up on the 00-SF forum and on the C&L web site, and both give credit to Martin but present the topic rather differently - with an emphasis on the track gauge and flangeways, not check gauge and crossing gap. At least that's how I read them!

 

Building track for 00 gauge is "different" to EM or P4 or whatever because you are most likely looking to build track to run your existing trains on, rather than building track for which you will then set up trains to a recognised and published standard. Now, I know my wheels will run through Peco Setrack and through 00-SF too and on a 16.8 mm gauge "radius 0" curve. I see this as the beauty of 00 gauge - tho' some will see it as showing how sloppy it all is. The thoughts behind my last post were to do with aesthetics and symmetry. For example suppose I want to make a turnout with a 24 inch curve (I want two). Martin's figures:

Radius inches     Track gauge mm     Check rail gap mm

     24              16.35             1.15 

 

This is just enough to look asymmetric. Suppose I make the crossing flangeway 1.1 mm, keep the 15.2 mm check gauge, and set up the stock rails to suit, it still ought to work. I know I can't call this '00-SF' but if it works with my trains and looks presentable, it's done its job.

 

My present layout has eight turnouts. These consist of one Peco Setrack, three Peco code 75 Streamline and four "to be home made" (one out of four done). The idea was that all my collection will run on most of the model, and most of my collection will run on all the model. Sort of Pareto without the numbers. I think for once in my life this was quite an intelligent decision.

 

We have written about train set curves. It is worth pointing out, the crossing gap for a Setrack turnout is nearer 2 mm, not the 1.3 mm of 00-BF ... but guess what. Lay a 15.2 mm check gauge on top of it, and while it doesn't fit the track (because the code 100 rail is too wide), it matches up very well.

 

This all leaves me with one more question! My back to back gauge is a Markits one, stamped "00" on the end and it measures 14.5 mm, not the 14.4 mm mentioned earlier. It often fits snugly into RTR, it's rarely a loose fit, but sometimes I need to tap a wheel out just a few thou along its axle. Is it a case that the specification dimension is (say) 14.45 mm, with a tolerance of +/- 0.05 mm, or is it something more subtle?

 

- Richard.

 

 

 

[AndyID]

Hi Richard,

 

I think you'll be OK with a 1.1 mm flangeway because you have a large angle at the crossing. With small angle crossings, the extra 0.1 mm translates into quite a large increase in the linear distance between the bend in the wingrail and the tip of the vee nose. That can allow a wheel to drop into the void, and that can result in derailments, particularly when propelling wagons through a turnout.

 

Personally, I prefer to go for the most reliable operation, so I stick rigidly to the 1.0 mm flangeway. The check-rail gap might be aesthetically a bit less pleasing, but then, if I was trying to achieve the most authentic appearance, I would have to use P4, and I'm too old to consider that!

 

Best,

Andy

[martin_wynne]

With small angle crossings, the extra 0.1 mm translates into quite a large increase in the linear distance between the bend in the wingrail and the tip of the vee nose. That can allow a wheel to drop into the void, and that can result in derailments, particularly when propelling wagons through a turnout.

 

Hi Andy,

 

This is a common misconception. The length of the crossing gap is largely irrelevant. It is the width of the gap which allows some wheels to drop into the crossings. The width of the crossing gap is at its widest just in front of the nose of the vee. There it is approximately twice the flangeway gap, and it is the same at all crossing angles, even very flat angles -- the widest part of the gap is always the same. Providing the wheels are wider than this, as they should be, it is physically impossible for them to drop into the gap at any angle. That's why the crossing flangeway gap is important -- small changes in the gap are doubled in their effect.

 

It is true that if the wheels are too narrow for the track standard (or put another way the flangeway gap is too wide for the wheels), then the effect of their dropping into the crossing will be more noticeable on long crossing angles than short ones. But if the wheels are wide enough they will remain fully supported on the wing rails, and will not drop in no matter how long the crossing angle.

 

This is the whole point of 00-SF -- the narrower crossing flangeway allows 2.3mm wide kit wheels to run smoothly fully supported through crossings. They don't do so on 00-BF because 2 times 1.3mm is 2.6mm -- the gap is wider than the wheels, and they can fall in.

 

But 2.8mm RTR wheels are fine and can't fall into a 2.6mm space, at any angle.

 

If you are using ONLY RTR wheels then there isn't a lot of reason to use 00-SF, apart from the improved appearance. You may as well stick with 00-BF, especially at small radii. It is only when you want to mix kit wheels and RTR wheels on the same track that 00-SF comes into its own.

 

I've written all this over and over again on RMweb, and I can't believe I'm writing it again. Time for someone else to write this stuff?

 

regards,

 

Martin.