Track Geometry

[Silver Fox 17]

Going by the dimensions in the brochure it seems the point will not fit into a curved part of a layout. Its radius is far greater than the 4 mentioned, also, the 6th radius is slightly different to the point.

It does seem unusual to not be able to put a point on the curve matching the curves radius.

[Fishmanoz]

Straight dimensions (from Anyrail) - 164mm for standard, 82/41 for half/qtr.

Radius for points and crossings - R6, 15 degrees.

The R6 curve (half curve 15 degrees) brings a point/crossing exactly back to parallel (sorry Garry, beg to differ).

I was pleased to see point dimensions like this, they are effectively streamline not standard. Everyone will thank Hornby in the long run for this with fewer derailments.

Have yet to do any playing in Anyrail to see what happens when R6 is used as the first 15/30 degrees of a 90 degree curve at each end of a loop (think start the curve with a point each end) - will set tracks straights match up between them or will flex be needed?

[RDS]

The R6 curve (half curve 15 degrees) brings a point/crossing exactly back to parallel (sorry Garry, beg to differ).

 

 

Sorry Fishy, I beg to differ as well.

I have it direct from AnyRail that the point is 631mm Radius and Rad is 640mm.

[D9020 Nimbus]

The track range seems to be related in some way to the Tillig TT "Modellgleis" but with a number of differences. The standard Tillig EW1 points are 129.5 mm long with a radius of 353 mm and 15 degrees. The compensating curve is equivalent to one of those in the Hornby range, but an additional straight track is needed to be equal to the curved arm of the point. The range of lengths of straight track in the Tillig range is greater; adding a 36.5 mm straight track brings the standard length of 166 mm.

These points are, if I am reading the German in their catalogue correctly, what Peco would call "Unifrog"; the frog area is by default dead but it can be powered and its polarity changed using a relay which they can supply.

The one thing to watch with points in the Tillig "Modellgleis" range is that they are non-latching. Unlike almost all points for the UK market, they are not sprung and require either a hand operating mechanism or electric operating mechanism which attaches to the side which must be purchased separately. They can also be operated by an under-baseboard motor of a suitable type.

There are a number of points in the range that are not in the Hornby TT:120 range; these include a 3-way point, a scissors crossover and a double slip. Hopefully it will be possible to fit the two ranges together.

There are EW2 points in the Tillig range exactly the same dimensions as the Hornby points, but these are live frog and intended for use with flexible track; the largest radius in the Tillig range is 390 mm. They aren't fitted with rail joiners, and can only be used with the under-baseboard motor.

[CORKY.]

I always thought it a shame that radius 4 in OO would not fit on a UK 8 X 4 sheet of ply, and resorted to the flooring size 10 X 5. I had never heard of TT, well ,I had, but that was Twix Twin that I owned as a boy, and nothing to do with the newTT. ....@RDS, thank you for the info that R4 fits an 8 X 4 board, I had received written info from a national retailer that the track overhung ,and I never measured it ! New 8 x 4, 4 loop layout in the planning...in your 8 x 4, 22mm do you still use battens?

[RDS]

I always thought it a shame that radius 4 in OO would not fit on a UK 8 X 4 sheet of ply ..

 

 

I don't know who told you that because it does and that is exactly what I have:

4 concentric Loops, Rad 1, 2, 3 and 4 with 19 sidings in the middle all on an 8 x 4 board of 22mm ply.

[96RAF]

Pending release of an official diagram please see this prelim copy. You will have to ref to each product page for dims.

[D9020 Nimbus]

The Tillig range of track includes a straight track whose length can be varied. It could be that the extended straight track listed in the catalogue is similar. Tracks of this nature have been made in the former Fleischmann Profi-Track range in HO (this range is no longer made) and are still available from Fleischmann and Kato in N gauge. There may be more.

Despite the different radius, the T8007 track does match the points — in AnyRail at least. Points are not always exactly part of a circle. Perhaps the slightly larger radius is needed to allow for a straight section of the points.

[Fishmanoz]

Agreed on defining a point. What I’m meaning is the degrees of turn between the toe end and the turned heel end plus the radius of the arc going through the mid points at each of these ends. That certainly matches the Radius 6 curve. And the end to end length of the point plus the R6 is the same as two standard straights.

And I’d be surprised if the extended straight isn’t twice standard straight length, happy to be proven wrong.

[D9020 Nimbus]

Which also makes my suggestion of a variable-length track unlikely too, perhaps.

[96RAF]

According to Hornby it is an extended half straight used to form a passing loop round a platform. The product page will be amended to suit.

[5Dublo2]

According to Hornby it is an extended half straight used to form a passing loop round a platform. The product page will be amended to suit.

 

 

As that problem has existed right back to Hornby Dublo 3-Rail I guess it is about time it was addressed with a correct length of track

 

 

(I should say I am happy someone has thought about it)

[Fishmanoz]

So it goes between a point and an R6 curve, bringing it back to parallel with a platform width between?

[96RAF]

@fishy

...the R6 curve gets you back to parallel - see left hand side siding in track diagram earlier. The extd straight either goes in the bus stop straight to fill an odd gap or more likely you use two as you say between the point and R6 to space the bus stop track wide enough to go round a platform as well as filling that odd gap.

[RB51]

Right. So used on its own R6 gets you parallel tracks and with the extension in between the point and R6 gives parallel track wide enough to accommodate a platform? R-

[5Dublo2]

@fishy

There are two things this extended straight needs to achieve

• setup the correct spacing for having a platform inside the loop
• match the settrack geometry so that the joins of the parallel sections of track in the loop and the main line end together and are not misaligned

It is the second of these two points that historically (in OO gauge) it has been difficult to do (even when using the short straight pieces) as all of the various solutions got close to alignment but were never perfect. It was usually better to cut some custom lengths of track as a work around

As an aside, in terms of getting back to parallel tracks after a point, it is not the radius of the curve that gets it straightened up, it is the angle. What the radius (in combination with the length) achieves is the correct parallel spacing and join alignment of those parallel tracks.

[5Dublo2]

I have just noticed something that those familiar with OO gauge SetTrack curves may need to be aware of

• In OO a full circle is made up of 16 Standard Curves (of 22.5 degree angle)*
• In TT a full circle is made up of 12 Standard Curves (of 30 degree angle)

*Note: a lot of OO layouts will use 8 Double Curves (of 45 degree angle) instead

[96RAF]

Right. So used on its own R6 gets you parallel tracks and with the extension in between the point and R6 gives parallel track wide enough to accommodate a platform? R-

 

 

Hopefully. Until someone sets it out ‘tis but presumption by me based on Hornby assurance.

 

 

[Fishmanoz]

Thanks for those replies everyone, most enlightening.

One thing I know, that extended track piece is yet to show in my Anyrail library, but maybe it’s already in an update I don’t see in my trial copy.

One thing I noticed - the qtr straight at 41.5mm is practically the same length as the standard track spacing, a benefit that helps to make some loop/siding variations work with only set track.

[Fishmanoz]

Look up the extended straight in the TT catalogue - it’s there and says it’s to fit between half and full straight. And it shows the length to be 92mm.

That’s an odd length in comparison to the ordinary straights but I’m assuming when you incline it by 15 degrees, you get a horizontal length (92 X cosine (15degrees)) of 83mm = half straight length.

[Fishmanoz]

Did you notice the platform end ramps you can get on pre-order are designed to go with Y points which are yet to be made available?

[Fishmanoz]

Also, the vertical distance for 92mm at 15 degrees is 24mm. That means the track spacing to take the 48mm wide platforms is 67mm.

[Fishmanoz]

Assuming Tillig Modell track is compatible with Hornby, you can buy their double slips to add to the Hornby range.

Or you can make one up using their 30 degree crossing and 4 Hornby points, or even a combination of Hornby points and crossings.

Also, the gap between the points/crossings from having the Tillig crossing in the middle comes out at 83mm so a half straight fills it. The gap between the parallel tracks is 65mm and the overall length is 415mm.

If you are having trouble understanding that, you can do the design in Anyrail to see what I mean. That’s what I did.

[RB51]

The Hornby TT:120 track library is now available on the SCARM blog in a Beta test capacity. It will be included in the next full release in the coming weeks.

R-

https://www.scarm.info/blog/

[96RAF]

The Scarm author has requested that if you see any anomalies in the new TT:120 library that you feed-back to him on the blog page.