Track Geometry

[Fishmanoz]

Does it include the mysterious “extended straight” in the library? Anyrail yet to.

I’ve used a lot of Tillig flex track in my design to get over spacing issues and because it’s better in practice anyway. Solves the lack of extended straight too.

[RB51]

Yes Fishy TT8037 is there. R-

[96RAF]

@Fishy

Hornby state the length of TT8037 as 92mm and its intended use is to gain width at a point curve to accommodate a platform. The 166 ID is a standard straight track length.

[Fishmanoz]

Thanks Rob, had all of that. And the track spacing it produces is about 67mm leaving the gap between tracks to accommodate the 48mm wide platform.

I’ve used a different configuration - I’ve used a flex straight 170.76mm long instead of the 8037 and placed that between crossover points. If you use that as the hypotenuse of a right angle triangle with angles 30/60 degrees, you get:

• a horizontal run of 166mm or a standard straight
• a vertical run of 40mm which, when added to the standard 43mm spacing produced by the points gives you a track spacing of 83mm or a half straight

That means all of your runs and gaps are standard length/height and you can connect up a loop running around the top of the platform in your diagram using standard track pieces for the remainder of the loop.

I think Hornby should consider adding this 170.76 straight to their range.

[StuLarge]

Not meaning to reignite TT8037 discussion (just happy I found this thread using the new forum search!)

Not got either the track pieces or Anyrail to hand at the moment but wondering how the above geometry matches the below.

 

[Herbie]

They leave a different size gap, but I don't have any platform pieces to see how they compare or look in real life.

[Moccasin]

Just idly playing in rail modeller express and using that 1st radius curve at both ends, a loop is pretty much ok (some minor gaps required in the loop but they do line up) if you use an extended half straight in the mainline and a half straight and quarter straight in the loop. Obviously, a 6th radius curve would work instead of either point,. or you could use an opposing sided point to create a stub/headshunt.

[StuLarge]

Thank you both, greatly appreciated 👍🏼 

[Moccasin]

Incidentally, the 2024 catalogue suggests similar 1/4 curves are coming for other radii. One of those might close the gap and align better, as well as being less tight. Presumably the 1/4 R1 is so short that it’s less of an issue for models nominally unable to cope with R1. 

[Fishmanoz]

One thing to note here: TT:120 points are “streamline” points with a radius of R6 (compare with OO points which have a radius of R2).  However, by adding the 1/4 R1 on the end of them, you are reducing the effective radius to less than R6.

Consequently, you may have a little more difficulty traversing this composite than the point on its own.