7mm Making a common crossing for 7mm or S7 (the hard way)

[iploffy]

Ditto Templot is as TOYAH used to say A Mystery to me

 

[Dog Star]

I really must learn how to use Templot! At least then I might be better equiped to grasp what an earth people are talking about

Ditto Templot is as TOYAH used to say A Mystery to me

I so agree with you guys, I spent days trying to get to grips with the program and I have given up because I could not comprehend the thinking behind the design. I was given a box file with templates and I could find no easy way to either display or print the material.

Please, no discussion of Templot here, use the appropriate parts of Templot Club.

 

[martin_wynne]

the numbers look correct for circa 1910 S&C work, I am not sure about pre-1900 turnouts for I think that some of the switch rails are at variance in the region 15'-24' lengths.

The "numbers" in Templot are just a small collection of pre-sets for your convenience. You can enter any other numbers of your own as a custom switch to match your prototype.

GWR used curved planing for switch rails... rather than "mill" the curve the switch rail was bolted to the planing table with the rail set to the required radius, the rail was then finished with straight planing and the clamps released. Boing! switch rail returned to original straight form with the end of the switch "planed" in a curve!

The Templot pre-sets include the full range of GWR straight and curved switches, loose-heel and flexible.

regards,

Martin.

 

[martin_wynne]

I so agree with you guys, I spent days trying to get to grips with the program and I have given up because I could not comprehend the thinking behind the design. I was given a box file with templates and I could find no easy way to either display or print the material.

It's extremely easy to do that. One quick question on the Templot Club forum would have received lots of friendly help: http://85a.co.uk/forum/

Please, no discussion of Templot here, use the appropriate parts of Templot Club.

I'm happy to answer Templot questions here for those who prefer.

regards,

Martin.
----------------------
http://templot.com

 

[Dikitriki]

If there are going to be a number of Templot questions, we should have a separate section elsewhere, rather than respond on this thread, which is I think what is behind Graham's comment. I too would recommend the Templot Club forum as a first port of call.

Richard

 

[Dog Star]

Please, no discussion of Templot here, use the appropriate parts of Templot Club.

I'm happy to answer Templot questions here for those who prefer.

regards, Martin

On reflection I can see that my comment (above) might be taken as a dimissive criticism - that was not intended and I apologise without reservation for any upset which has been caused by my comment. I read the Templot digest daily and I am aware of Martin's concern, expressed within that forum, that he wished that all questions about Templot be discussed and resolved within the Templot Forum (rather than, for example, by e-mail correspondence). My comment was intended to be in the spirit of compliance with Martin's request.

regards, Graham

 

[martin_wynne]

Hi Graham,

No upset and no apology needed. I am indeed concerned not to receive direct one-to-one enquiries (to which there is an obligation to reply), but I'm happy to answer on web forums (to which there isn't) whenever I can. Templot Club is the obvious forum to use, with several experienced users happy to help, but I long ago gave up trying to get all all Templot users to join there. There are often days when there is more Templot discussion on RMweb or the Scalefour web forum than on Templot Club.

It's unfortunate that there are so many web forums with the same information often repeated and scattered here there and everywhere, with no central clearing house or index.

regards,

Martin.

 

[Dog Star]

Sometime back I started a thread about Jigs and Gauges for 7mm track making, the content of that thread being a description of the various items that I use in 7mm track making. At that time I did not describe one specific gauge which is available from the S7 Group Stores simply because the particular gauge was one which I did not use in construction.... until now, so watch out for the flangeway gauge in this post.

After making a jig for checking the fit of point and splice rails and then assembly of those rails into a Vee, the next step is to make a jig for assembly of the common crossing. The crossing assembly jig was started in an earlier post so to continue with the fences for the wing/closure rails. The flat ply pieces to the left hand side are aligned with the vee stop using a straight edge whilst the glue dries, the position of the pieces is to allow for soldering of the flat brass strips which join the rails to form the crossing:-



So with the jig complete - pending any changes found to be necessary as the crossing is assembled - the vee is placed in the jig and pushed gently against the vee stop:-



Next step is to place a wing rail - over length to make holding the rail easier - in the jig and check alignment of the wing against the vee. The curve through the knuckle and the fore-aft placing of the wing rail are adjusted until the Flangeway gauge shows a constant clearance between the wing and the vee. The wing rail is held firmly and temporarily in position with a wedge (same angle as the vee) whilst checking alignment:-



Ah, what about forming the curve through the knuckle? Well. behind every S7 modeller there is a bodger of varying competence and I claim to be as much a bodger as the rest of the fraternity. The wing rails of the LNWR circa 1900 had a decent curve through the knuckle, from 10'0" to 40'0" dependent upon crossing angle - for 1:8 angles the curve radius appears to be 20'0" whilst the curve for 1:8.5 appears to be 40'0" (if these numbers are not correct then that is down to the poor quality of the drawing... ).

I have used 20'0" radius for this crossing and formed the curve using a "bodger's aid" - looking around for a curve of radius 14cms I found that one of these had a suitable diameter:-



Actually I used this one, with a diameter of around 16cms, to form a curve in some rail and then used one with a 26 cms diameter to achieve a more prototypical bend when adjusting the rail to fit the jig / vee:-



When producing the second wing rail, bend the rail t'other way to produce a pair of wing rails (one LH and one RH).

regards, Graham

 

[Simon]

Crikey Graham, your crossings really do look good

Note to self, must try harder. Mind you, I'm doing it without jigs and with that pesky rail inclination but nonetheless I'm going to try and improve my fit of point and splice rail.

It's very helpful actually seeing the shapes you have created "in plan". Despite studying my "British Railway Track" I can now see at least one misapprehension under which I have been labouring

Out to the shed methinks if I can avoid getting too involved in chicken roasting and vegetable preparation.

Great stuff, keep up the good work!

Simon

 

[Dog Star]

...It's very helpful actually seeing the shapes you have created "in plan". Despite studying my "British Railway Track" I can now see at least one misapprehension under which I have been labouring...

I shall try to remember to bring a completed turnout when I next visit the "Greatest Little Bookshop in the West" ( to plagarise and paraphrase a film title).

regards, Graham

 

[Simon]

You are very kind

Right I really must get up and do something

Simon

 

[phileakins]

Crikey Graham, your crossings really do look good

Note to self, must try harder. Mind you, I'm doing it without jigs and with that pesky rail inclination but nonetheless I'm going to try and improve my fit of point and splice rail.

Simon, actually there is no rail inclination through the common crossing.

Phil

 

[Dog Star]

Simon, actually there is no rail inclination through the common crossing.

You do not want to know that some LNWR drawings circa 1900-1910 specify cant through the crossing... did you.

Good , because I have not done that , too difficult to get the Vee done with cant .

regards, Graham

 

[phileakins]

You do not want to know that some LNWR drawings circa 1900-1910 specify cant through the crossing... did you.

Good , because I have not done that , too difficult to get the Vee done with cant .

regards, Graham

I'm so glad you didn't tell me that Graham - I've got nothing relevant going back that far (I thought I had but I can't find it at the moment).

Cheers.

Phil.

PS I've now done what I should have done in the first place! My 1956 copy of 'British Railways Track' confirms that the bullhead rail through the crossing is canted, it is flat bottomed rail which is vertical from the crossing nose throughout the planing and then twisted to 1:20. Anyone fancy modelling that.

 

[Dog Star]

I am not sure how I would start to incorporate cant through a Vee (with Bullhead Rail)... and the filing / assembly jigs from the S7 Group are designed to produce a crossing with vertical rails for the vee and for the wings. As the Exactoscale chairs incorporate cant in the moulding this presents an interesting problem for the plain / bridge chairs that hold the legs of the vee and the free ends of the wing rails.

After forming the common crossing I put a small amount of twist into each leg of the vee, between the last block chair and the first plain / bridge chair. By introducing cant in this way there is no stress in the individual chair mouldings. If there are plain / bridge chairs on the wing rail then the same action is applied. The LNWR pre-1900 common crossing does not have single chairs between the knuckle and the closure rails so that crossing has no cant, the circa 1909 common crossing does have single chairs adjacent to the closure rails hence those crossings do have cant introduced into the free-ends of the wing rails.

Simples!

regards, Graham

 

[Simon]

When you chaps say "cant" I take it you are referring to rail inclination rather than "banking the curves" in a permanent way imitates Scalextric stylee?

Putting Cant through a crossing is a pretty mind blowing concept as far as I can see, I did "bank" the toe of the turnout that is actually laid out on my garden line but the cant runs out before getting to the crossing.

Trackwork, a splendidly complex subject once you get into it - anyone for versines?

Simon

 

[Dog Star]

There is a good chance that Simon is correct and that I may have used one term to describe a different facet of trackwork, I shall consult my copy of a GWR PW pamphlet as read at a Swindon Engineering meeting circa 1896.

Thereafter I shall correct my posts if correction is required, we do not want to be mis-leading people...

Versines? very devious little equations which can give a nasty kick when one is not looking.

regards, Graham

 

[Locomodels]

Versines? very devious little equations which can give a nasty kick when one is not looking.


Go on, you know that you love them really!!

 

[phileakins]

I am not sure how I would start to incorporate cant through a Vee (with Bullhead Rail)... and the filing / assembly jigs from the S7 Group are designed to produce a crossing with vertical rails for the vee and for the wings. As the Exactoscale chairs incorporate cant in the moulding this presents an interesting problem for the plain / bridge chairs that hold the legs of the vee and the free ends of the wing rails.

After forming the common crossing I put a small amount of twist into each leg of the vee, between the last block chair and the first plain / bridge chair. By introducing cant in this way there is no stress in the individual chair mouldings. If there are plain / bridge chairs on the wing rail then the same action is applied. The LNWR pre-1900 common crossing does not have single chairs between the knuckle and the closure rails so that crossing has no cant, the circa 1909 common crossing does have single chairs adjacent to the closure rails hence those crossings do have cant introduced into the free-ends of the wing rails.

Simples!

regards, Graham

@Graham

Yes, that's the way I do it and for the same reasons, but with the insertion of a great deal of bad language whilst putting the right amount of twist in each component.

@Simon.

I think the proper term for what you describe is 'super-elevation'.

I'll have to say no to a versine thanks - I had to give them up on medical advise.

Phil

[Edit] Back to the book!

"The terms 'cant' and 'superelevation' are both used to represent the amount by which the outer rail of a track is raised above the inner". British Railways Track (The Permanent Way Institute, 1956) [/Edit]

 

[Dog Star]

I am going to go with Simon's comment and Phil's corroboration and amend the text of the above so that "cant" is used for the elevation of one rail relative to another and "inclination" is used for an individual rail.

Apologies for a senior moment.

regards, Graham