Peco medium points crossover

[Brian-1c]

Hi,

 

I want to use Peco medium N gauge points to form a crossover between two parallel tracks, but using the standard track spacing for Code 80 curves. However, only the short 1st radius points joint at the right spacing. Clearly, I need to cut two pieces of track to length to match the gap between the two medium points, as well the matching straights on the other track.

 

I have made this picture using Scarm, which I hope illustrates the "point"  

 

Can anyone help me with the correct length of track for either, or both, tracks A and/or B please ?

 

 

[jpendle]

Hi,

 

Do you have a printer? SCARM let's you print out full size plans, so you could just print it out and measure the gaps with a ruler.

 

Alternatively, use the tape measure tool in SCARM.

 

Regards,

 

John P

Edited May 30, 2021 by jpendle
Correction

[Brian-1c]

Hi John,

 

Thanks for the reply, but I could only do that if I could accurately line them up in Scarm, which I cannot do. That's not important though, as Scarm is a very useful tool for designing the layout and this can be done on the screen approximately, as, in fact I have done above. However, when I get to the proposed layout, I still need to get precise line up and for that I do need the precise length of one or other track, if anyone knows this please.

[Pete the Elaner]

Hi,

 

ST-5 indicates Setrack which uses track made to fixed lengths/radii.

SL signifies the streamline range. Streamline has no straight or curved sections. They intended to work with flexible track.

Peco's web site has the dimensions of their products & shows the medium points to be 123.7mm in length. If you are not joining the points directly to each other then dimension A would need to be longer than that.

I therefore assume that by 'standard track spacing for code 80 curves", you mean Setrack spacing, not Streamline spacing?

You may find flexible track is easier to manipulate than Setrack because it is intended to be cut & curved.

I don't know what dimension B would be.

[jpendle]

Hi,

 

So Scarm will tell you the precise length of every piece of track on the layout, but to design the track the way you indicate means that you have to line up the right most turnout by eye.

I did this by attaching two ST11's to the toe of the lower ST5 and the diverging route of the upper SL-E395, I then lined up the second SLE-295 by eye, deleted the two ST11's and then joined the point up using Flex track. Scarm then gave me dimensions of 5.9" for A and 1.2" for B.

Unfortunately we can't attach Scarm files here. But I've attached a .jpg file.

 

 

Regards,

 

John P

[ejstubbs]

It's a trigonometry question.  To get the length of the additional straight piece, take the Streamline standard spacing away from the Setrack standard spacing and divide by the sine of the diverging angle of the Streamline turnouts (12° on OO, I don't know whether it's the same in N).  So, for a pair of turnouts as drawn by the OP, in OO it would be the Setrack track spacing of 67mm, minus the Streamline track spacing of 50mm, divided by sin(12) = 81.77mm.

 

When I'm doing layout design I keep a small Excel workbook handy into which I can plug the X or Y coordinates of two track end points and read off the length of straight track required to connect them at various different angles (based on combinations of Setrack and Streamline geometries).

[Chimer]

Surely, just lay the points where you want them and cut flexi to fit the gaps?  Even if you know it theoretically needs to be (say) exactly 81.77mm, you can't cut to anything like that accuracy, so why worry?

[Flying Pig]

43 minutes ago, ejstubbs said:

(12° on OO, I don't know whether it's the same in N)

 

Code 80 medium points are 12° according to Peco's website, but other N gauge items have different angles.

 

BTW a feature that I found very useful in XTrackCAD when I used to use it was the ability to snap a point onto the the intersection of any two lines crossing at the correct angle for that point.  It made situations like this really easy: lay the two main lines spaced with the Setrack crossover using a length of flexi for the lower one and including the upper of the medium points; then add a length of flexi to the diverging line of the medium point and drop in the second point where it crosses the lower main line, forming the crossover.  As with Scarm, you can read off the resulting track lengths.  Unfortunately, this feature doesn't seem to exist in other programs.

[Brian-1c]

11 hours ago, ejstubbs said:

It's a trigonometry question.  To get the length of the additional straight piece, take the Streamline standard spacing away from the Setrack standard spacing and divide by the sine of the diverging angle of the Streamline turnouts (12° on OO, I don't know whether it's the same in N).  So, for a pair of turnouts as drawn by the OP, in OO it would be the Setrack track spacing of 67mm, minus the Streamline track spacing of 50mm, divided by sin(12) = 81.77mm.

 

When I'm doing layout design I keep a small Excel workbook handy into which I can plug the X or Y coordinates of two track end points and read off the length of straight track required to connect them at various different angles (based on combinations of Setrack and Streamline geometries).

 

Thank you, that's exactly what I was looking for, my trig is more than a bit hazy from non use over too many decades.

 

Thanks also to Flying Pig for confirming the angle.

 

It was only a matter of seconds to get an answer of 38.5mm after that.

 

I had no chance yet to try it with actual track, as I am waiting for the points to arrive. Also, this is a temporary solution for a bit of test track whilst I get the real layout built. The latter will be all Code 55 so will not need the bridging piece from that "point". 

 

Thanks to all who responded, it really will save me some time in putting it together.