Track Geometry

[Michael-782895]

Are Hornby going to publish a track geometry guide. I guide like to work out if a window sill layout would work for me.

[Yelrow]

Michael. Hi, if you post the size of your window sill we as existing users would be able to tell you.

[96RAF]

An associated TT track planner, either app based or scaled plastic parts would also be worth investigating.

I note the catalogue shows rads 1, 2, 3, 4 and 6 but no 5.

[ellocoloco]

On the wild assumption that Hornby's TT track will be compatible with Continental manufacturers and presumably be offered under the Arnold brand into that market, it won't be too far off that sold by Tillig. That is - R1 267mm, R2 310mm, R3 353mm and R4 396mm.

Best guess until more detail comes out.

[Fishmanoz]

That is exactly the geometry. It is buried in the Hornby detail in one of the two listed publications.

I don’t believe they’ve yet told us the radius of points or crossovers, but points shouldn’t be too hard to figure from the Trackmat.

[Dav2]

A few month ago Peco themselves started doing TT track. They will probably also have the geometry.

[Yelrow]

Dave, Peco, have been making TT Flexitrack,metre long, for many years. Mine is at least 10 years old

[ntpntpntp]

Anyone know the rail code Hornby are using for their track? I presume it's code 55 like the Peco TT:120 track?

[Hobby11]

Code 80 I'd expect NTP, which would be compatible with Peco's code 55 which really isn't code 55 but 80 with an extra "foot" in the middle!

[Rana Temporia]

I think the confusion with the PECO track is that the new pointwork is based on British practice, the older 12mm gauge pointwork was for narrow gauge representing 3’ or 1m gauge prototypes and may have been based on US practice. I’m sure someone will confirm this.

[ntpntpntp]

Code 80 I'd expect NTP, which would be compatible with Peco's code 55 which really isn't code 55 but 80 with an extra "foot" in the middle!

 

 

So the same as the N code 55 then. Must admit I'd not looked closely at piccies of the Peco TT track, but now you mention it yes it is the same "double T" rail section. Interesting. I've used the N code 55 since the 90s. If Hornby are indeed using code 80 then there'll be the same slight step in the rail top if you try and join the two codes together (the "double T" rail is actually more like code 83 at full height). On my N layouts I only ever mix the codes by alignment at baseboard joints - no joiners used.

[Hobby11]

I think the confusion with the PECO track is that the new pointwork is based on British practice, the older 12mm gauge pointwork was for narrow gauge representing 3’ or 1m gauge prototypes and may have been based on US practice. I’m sure someone will confirm this.

 

 

Yes the old stuff was (and is) called H0m track (H0 scale, 1:87, 12mm gauge for metre gauge prototypes). It's based, I believe, on Swiss practice and is also code 75, not 80, not that there's much difference! (Ex modeller in H0m, though German rather than Swiss!).

 

 

[Hobby11]

Code 80 I'd expect NTP, which would be compatible with Peco's code 55 which really isn't code 55 but 80 with an extra "foot" in the middle!

So the same as the N code 55 then. Must admit I'd not looked closely at piccies of the Peco TT track, but now you mention it yes it is the same "double T" rail section. Interesting. I've used the N code 55 since the 90s. If Hornby are indeed using code 80 then there'll be the same slight step in the rail top if you try and join the two codes together (the "double T" rail is actually more like code 83 at full height). On my N layouts I only ever mix the codes by alignment at baseboard joints - no joiners used.

 

 

I've been mixing code 80 and 83 for decades in H0e, the "step" isn't really noticeable and you can always put a file to the code 83, though I never have done!

[frey-1222498]

Hi

I just got off there phone with Hornby Tech and I asked if this was the same code as tillig Bahn track and it turns out that the hight of both rails are the same as they had a piece of Tillig track in the office, he did say that the fish plates would be a problem but if you were for example to purchase a tillig slip or double crossover you could solder the Hornby and Tillig track together which I have done in the past with OO track with just a bit of filing and polishing and your done.

[Hobby11]

Hi Frey. the "foot" is slightly different for the two ranges (Peco and Tillig), I'm trying to remember which has the larger "foot" but can't! I just used the joiners of the one with the larger foot, saves having to solder! The "unitrack" set up is more an issue, I'd suggest, as it makes the track higher.

[RB51]

Yes, I purchased a short length of Tillig to try it out, and had been told in advance that a shim of some kind would be needed to bring the tracks to the same height. Similarly I can’t remember which one needed raising but my guess is it was the Tillig as the piece I got did not have ballast. R-

[frey-1222498]

Hi Hobby

I may order a small piece of tillig straight along with a building I'm looking at from model Bahn union and check if its possible when my Hornby track arrives, The Hornby guys said it would be possible but before I buy an expensive piece of tillig track this may be the best way to be sure.

[Hobby11]

Good idea, if you are UK based there are UK stockists for Tillig, not sure if it's ok to post this, Mods delete if you don't think so: https://www.tillig.com/eng/grossbritannien_irland.html

[frey-1222498]

Thanks for that Hobby, yes I'm London based. Will start checking out the sites for these shops. Frey

[ntpntpntp]

I've been mixing code 80 and 83 for decades in H0e, the "step" isn't really noticeable and you can always put a file to the code 83, though I never have done!

 

 

I certainly find the step noticeable. I'd never apply a file to the rail top, causes too much damage. I did find that if necessary you can simply use a wood block and hammer to tap the rail down, deforming the joiner slightly and removing the step. However as I use code 55 on the scenic parts of the layout and code 80 only on hidden trackwork/fiddleyards the interfaces naturally occur at baseboard joints anyway :) I expect I'll go the same way with a TT layout if/when I get round to building one.

 

 

[ace2507]

I don’t believe they’ve yet told us the radius of points or crossovers, but points shouldn’t be too hard to figure from the Trackmat.

 

 

Hornby TT is now on AnyRail, the curve of the points is radius 6.

[Fishmanoz]

Another mistake in the detail published - if you look at the set contents in the brochure, it indicates the basic oval is R2. This is clearly not the case as the additional inside oval that comes in Track Packs 2 and 3 would then be R1. Then if that were the case, the inside curved siding in a later Pack would have to be a smaller radius again, and there is none.

So basic oval is R3 leaving R2 for the inside oval and R1 for the siding.

The detail in the Track Pack section is therefore correct, not the conflicting set detail. Although the set oval dimensions given are clearly for the correct radius.

Just rounding out the detail in this post and as stated elsewhere, the point and crossover radii are R6, hence the R6 curve used to bring the track back to parallel.

PS. Set description is now correct, brochure set description still incorrect.

[96RAF]

I notice none of the straight track length product pages have any useful dimensions. There is a half straight, a long straight and an extended straight and not a single clue as to their lengths.

Come on Hornby get a proper TT:120 track geometry drawing on site and update your product pages with meaningful tech data sooner rather than later.

[Herbie]

All track lengths are shown in the downloadable brochure, pages 24-25.

E.G. Standard straight is 166mm.

So a set of points is also 166mm which is only 2mm shorter than OO, so I'm not sure how much more track I'll be able to include in a layout.

[ace2507]

@SteveC I did a comparison on AnyRail, radius 3 in TT fits just inside radius 1 in OO.