Grade 1 and 2 curves

Thebaz · August 30, 2019, 10:16:42 PM

Hi all, first post so go easy! I'm looking at a model on ebay at the moment of something I particularly need for my yet-to-build layout. The current owner says they are selling because said model doesn't like the grade 1 and 2 curves on their layout. Silly question probably, but do I take this to mean the tightest radii? Not sure whether to take a punt as my plans do feature tight setrack radii. On the other hand there are no reverse curves to contend with.

njee20 · August 30, 2019, 10:18:13 PM

Slightly odd phrasing, but yes, that's what I'd infer.

What's the model? Most things are pretty tolerant of tighter corners. 9" ones can be problematic.

Welcome!

Thebaz · August 30, 2019, 10:23:04 PM

Thanks for the reply. The model is a Farish SWT liveried Class 170.

njee20 · August 30, 2019, 10:33:16 PM

The 170 is fairly long, so overhang on sharp curves will be an issue. I've never consciously run mine around a very tight curve, but if you're happy that it may struggle a bit on the very tightest bends then crack on.

It's an older model, no working lights and not DCC-ready, but mine runs really nicely I must say.

Newportnobby · August 31, 2019, 12:20:23 PM

Hi Thebaz, and welcome to the forum

Peco grade 1 = 229mm radius and grade 2 = 263.5mm.
Kato do a curve even tighter than grade 1.
I don't have such a thing as a class 170 but would have thought it would be OK on grade 2. I can't be positive, though.

Thebaz · September 02, 2019, 12:03:14 PM

Thanks all, I've bought it now so it'll have to work!

I will test it on some other layouts and if it doesn't work satisfactorily I will have to change my plans a little.

njee20 · September 02, 2019, 12:19:36 PM

On the presumption you have two concentric ovals (or similar) then it should be fine on the outer one at the very least. Mine definitely copes fine with c11" curves.

PostModN66 · September 02, 2019, 04:16:49 PM

My 170s All go round Kato 8.5inch curves without trouble. You might have to adjust the couplings but that is all.

Here is a video of the mechanically extremely similar (same powered chassis) 158 unit going round reverse curves on Deansmoor (Peco 9in Setrack points)

(Note - thee units have fixed valances so there is a customised coupling solution between the units, standard couplings within each)

Cheers

Jon

Newportnobby · September 02, 2019, 08:54:00 PM

Sorry to point it out but that's a nasty kink in the running line, Jon

PostModN66 · September 02, 2019, 09:19:20 PM

Quote from: Newportnobby on September 02, 2019, 08:54:00 PM
Sorry to point it out but that's a nasty kink in the running line, Jon

Outrageous!! I am mortally wounded!

Seriously though, it is because the two SetTrack points making the reverse curve are slightly different radii, so the second one doesn't bring the track back on a parallel course. I did consider replacing one or both, or minor surgery to slightly shorten one, but in the end I didn't bother. Soon enough they will need replacing anyway and the problem will sort itself.

It doesn't cause any practical problems and actually is not as bad in real life - the low camera angle foreshortens things a bit!

Cheers Jon