Code 125 Rail Dimensions

[Terry Downes]

Does anyone know of a drawing showing dimensions for code 125 rail?

 

[Terry Downes]

I'm trying determine whether this measured rail is code 125 or something else.

 

[Paul Boyd]

3.2 / 25.4 = 0.126 so close enough to Code 125!

 

[Terry Downes]

Hi Paul, it's the circled 0.75mm dimension which I'm finding difficult. to confirm as it seems to be much thicker than expected.

 

[Paul Boyd]

Hi Paul, it's the circled 0.75mm dimension which I'm finding difficult. to confirm as it seems to be much thicker than expected.

Hi Terry,

The rail code simply refers to the height of the rail, not the profile - it could equally be FB. You asked if it’s Code 125, which it is regardless of any other dimension.

What you actually need is a drawing of the full size rail that your code 125 BH is intended to represent, then scale from that. From your measurements. I would agree that the rail foot does seem a bit thick but without scaling from the full size, it’s difficult to tell. The bottom line though is that as modellers, we have to use whichever rail section is available to us!

Cheers,
Paul

 

[Martin Wynne]

@Terry Downes

Hi Terry,

The code 125 BH settings are already in Templot. John kindly sent me some to measure:

Here are the dimensions for C&L code 125 BH - you don't need these, just click the code 125 option above.

p.s. if modelling in S7, would it be better to use the correct scale BS-95R section - code 131 ?

// C&L code125 bullhead....

rail_section_option:=5;

// use measured dims converted to full-size at 7mm/ft ...

A rail_depth_mm:=(5+29/64)*inscale; // 5.29/64" - 3.18mm

H rail_fish_angle:=2; // 1:2 estimated

F // 2.3/16" - 1.28mm estimated from rail top to intersection fish angle on rail centre-line

rail_web_top_mm:=(2+3/16)*inscale;

G // 1.5/8" - 0.95mm estimated from rail bottom to intersection fish angle on rail centre-line

rail_web_bottom_mm:=rail_depth_mm-(1+5/8)*inscale; // from top

E rail_web_thick_mm:=(1+7/64)*inscale*(100+chair_web_adjustment)/100; // 1.7/64" - 0.65mm

B,D // other dims match BS-95R - head and foot width 2.3/4" - 1.60mm

C 1/2" - 0.29mm

cheers,

Martin.

 

[Terry Downes]

Hi Martin, I'm currently trying to resin print some 7mm chairs for John (AKA Hayfield) who has provided me with a sample of his C&L code 125 rail. I printed my first test GOG-F_S1_Chair using the default Templot setting/button as You have suggested but the rail is too tight and would not fit without breaking the chair so, I began investigating rail and chair sizes as below....

C&L Code125 measurements:
Using a digital vernier calliper I measured the supplied code125 rail as best I could (not easy) and created a CAD drawing of the rail periphery as below.
Note: black dimensions are measured and grey dimensions are resultant fish dimensions.
I then projected the fish angles to determine F,G and H dimensions.
I believe the offending dimension is bottom rail height of 0.70mm...

Templot 7mm GOG-F code125 Chair STL dimensions:
I have created a dimensioned section drawing of the exported .stl file from Templot using current default C&L Code 125 rail settings. This is what was utilised to create first Test print, without any shrinkage etc. This reveals a stl bottom rail height of 0.55mm which is too small for the rail I have.

I'm now going to try and generate a custom rail size and create/measure this new stl file BEFORE printing off more test chairs. I'll post results later.

 

[Hayfield]

I have had no real issues either printing chairs on COT track and plug track in FDM, however the rail is a tight fit in the chairs. FDM is far less brittle than resin and shrinkage in FDM opens up the slot.

Resin I feel is a bit more fragile plus overexposure/ surplus resin closes the gap in the slots ? or is this a false impression from my experiments

 

[Terry Downes]

I think I have discovered why my GOG-F chairs for code125 BH rail would not fit / kept breaking when I was using a standard resin rather than an ABS like resin!
This CAD image shows that there is interference between the 'measured' code125 BH rail and the current Templot 'C&L code 125' settings generated chairs. In reality the maximum interference shown below is 0.15mm (0.006" or 6 thou') which could potentially be accommodated by a tough ABS like resin but, not by standard resins which are much more brittle/fragile.

So, I have created a custom code 125 rail within Templot and achieved the following results. The CAD files show zero interference and the printed resin chairs slide on perfectly.

It would be interesting to know whether other 'Plug Track Creators' have encountered this with the Templot code125 settings or whether Anyone has actually printed any of these in any volume?

Below are the 'custom' code 125 Rail settings I used and will be using going forward. Martin, I'm not sure whether the existing settings within Templot should be altered until We get some more feedback etc.

I'm now going to test print some loose jaw chairs and see-crossing chairs etc for John.

 

[Martin Wynne]

@Terry Downes @Hayfield

Hi Terry,

Many thanks. All my original testing in 7mm was done with code 131 rail (why everyone uses under-scale code 125 is an ongoing mystery), and I did only a brief test with the samples of code 125 which John sent me. Which seemed ok, but it's obvious that the code 125 is very variable, just from those few samples.

For the FDM COT track there is an additional easing of the rail fit for both code 125 and 131, based purely on the practical results from the Neptune 4. That has obviously been masking the interference you found in the original settings.

I will change the code 125 settings to match yours, and then do some more testing of both resin and FDM COT.

Thanks again for your report. This is exactly why I keep saying it is still experimental and not really ready for practical use until we have had a lot more feedback.

cheers,

Martin.

 

[Terry Downes]

Hi Martin,
I wouldn't get distracted by altering the code 125 settings and testing just yet. I would suggest waiting a week/month or so to see IF there are any other users utilising code125 rail before making changes etc.

BTW, is there a way of saving my custom rail settings rather than having to re-enter each time? Again, this is NOT important so, please don't let me distract you from the crossing chair coding etc.

 

[Steve_Cornford]

Hi Terry,
go to the custom tab on the dfx export screen, then click on [save custom data ]button, & make the save as filename
something memeorable, like code_125_settings

Next time you load Templot, and need to use code 125 rail, go to the custom tab & click [load custom data] then choose your memeorable filename


Yuo can create as many save custom data files as you need...
Steve

 

[Martin Wynne]

Hi Martin,
I wouldn't get distracted by altering the code 125 settings and testing just yet. I would suggest waiting a week/month or so to see IF there are any other users utilising code125 rail before making changes etc.

BTW, is there a way of saving my custom rail settings rather than having to re-enter each time? Again, this is NOT important so, please don't let me distract you from the crossing chair coding etc.

@Terry Downes @Steve_Cornford

Hi Terry,

You have obviously done a lot of work on the rail settings, and I don't want to make folks wait to benefit from them. I'm also very keen to impress on everyone that the whole thing is still experimental and subject to change -- so:

we can have both.

cheers,

Martin.

 

[Steve_Cornford]

But which is which?

 

[Phil O]

I think I have discovered why my GOG-F chairs for code125 BH rail would not fit / kept breaking when I was using a standard resin rather than an ABS like resin!
This CAD image shows that there is interference between the 'measured' code125 BH rail and the current Templot 'C&L code 125' settings generated chairs. In reality the maximum interference shown below is 0.15mm (0.006" or 6 thou') which could potentially be accommodated by a tough ABS like resin but, not by standard resins which are much more brittle/fragile.
View attachment 13011
So, I have created a custom code 125 rail within Templot and achieved the following results. The CAD files show zero interference and the printed resin chairs slide on perfectly.
View attachment 13012

View attachment 13013

It would be interesting to know whether other 'Plug Track Creators' have encountered this with the Templot code125 settings or whether Anyone has actually printed any of these in any volume?

Below are the 'custom' code 125 Rail settings I used and will be using going forward. Martin, I'm not sure whether the existing settings within Templot should be altered until We get some more feedback etc.
View attachment 13015

I'm now going to test print some loose jaw chairs and see-crossing chairs etc for John.

Hi Terry,

That's pretty close to how the prototype sits in the chair, after a period rust and crud fills any small voids, requiring a good smack or two with the non key end of a keying hammer.

 

[Martin Wynne]

@Terry Downes

Hi Terry,

Here you go:

    if dxf_form.cl_125_rail_B_radiobutton.Checked=True    // option B TD 2024
       then begin
              rail_section_option:=7;

               // use measured dims converted to full-size at 7mm/ft ...

              rail_depth_mm:=3.18*sf*inscale;

              rail_head_width_mm:=1.62*sf*inscale;

              rail_corner_rad_mm:=0.29*sf*inscale;

              rail_foot_width_mm:=1.62*sf*inscale;

              rail_fish_angle:=2.0;          // 1:n

              rail_web_top_mm:=1.40*sf*inscale;        //  from rail top to intersection fish angle on rail centre-line
              rail_web_bottom_mm:=2.08*sf*inscale;    //  from rail top to intersection fish angle on rail centre-line

              rail_web_thick_mm:=0.65*sf*inscale*(100+chair_web_adjustment)/100;
            end;

edit: Sorry, there was an error in the above when first posted. Now corrected.

Thanks again. Will be in 556b.

cheers,

Martin.

 

[Hayfield]

@Terry Downes @Hayfield

Hi Terry,

Many thanks. All my original testing in 7mm was done with code 131 rail (why everyone uses under-scale code 125 is an ongoing mystery), and I did only a brief test with the samples of code 125 which John sent me. Which seemed ok, but it's obvious that the code 125 is very variable, just from those few samples.


Martin.

Martin

The simple answer is I still have 50m of code 125, as C&L sell code 131 @ £37.50 per 10m I have just under £200 wort of rail, I am a modeler not an engineer and work to 32mm gauge (which is under scale anyway) so from a distance who can tell whether its code 125 or 131 ?

Scale7 group stores only stock code 125 and its £27 for 10 yards, I guess the reason is both cost of the stock they own and Phil at C&L owns the tooling for code 131

 

[Martin Wynne]

Martin

The simple answer is I still have 50m of code 125, as C&L sell code 131 @ £37.50 per 10m I have just under £200 wort of rail, I am a modeler not an engineer and work to 32mm gauge (which is under scale anyway) so from a distance who can tell whether its code 125 or 131 ?

Scale7 group stores only stock code 125 and its £27 for 10 yards, I guess the reason is both cost of the stock they own and Phil at C&L owns the tooling for code 131

@Hayfield

Hi John,

I can see that you would want to use up the stock you already have, and that visually it is difficult to see the difference.

My real question was how did we get into the situation where there is so much code 125 BH in the system? Why was it made in the first place? My old track-building book from Slaters mentions "their code 131 bullhead rail" but they now deny that they ever produced such a thing. In the early years of C&L before Brian Lewis took over they used to produce 0 gauge flexi-track with code 131 rail.

In the 4mm world we have had exact scale code 75 bullhead for about 60 years now. I remember the flurry of interest when it was first introduced, I think by a firm called 00Scale Models. It seems strange that the 7mm world is still not routinely using scale bullhead rail, and that what they are using is actually under scale (in the old days all rail was over scale -- I remember helping with a large club EM layout using code 95 bullhead).

cheers,

Martin.

 

[Hayfield]

Martin

Being a recent convert to 7mm scale I have no idea about the history, but simply in past years UK railway modelers in the main are not interested in scale trackwork, some are waking up to the mishmash we have, but until companies like Peco only react when they face a threat from a competitor do they act, however they must be congratulated in working with the EMGS

The simple truth is finance, having the money for new tooling, then having the cash to invest in stock which stays on the shelf for ages.

As for code 131, I assume only the new range of C&L 7mm 2 & 3 bolt chairs have been designed to fit it, though seemingly LSWR and 4 bolt chairs (designed for code 125) do fit it.

John