What curve radius do you use

Hi      Im striving for 72'' radius or larger, but as you point out, this large a radius isn't all ways practical for a lot of spaces. I dont think this need spoil any ones fun. The same radius's used in three rail could still be used in two rail, if you can except moving pilots and blind drivers, and or smaller loco's. If you like operating on your shag carpet in your lounge you might have some issues staying on track, but apart from that, well laid track is the secret. Im going to say that a 48'' radius would allow some fixed pilot diesel and smaller all flanged steamers.           cTr.....(Choose the Right)

Have seen a 2 rail layout where their MTH 2rail Northerns front drivers derail on the less than 7 foot radius curves. It will be fixed wheelbase steam engines than anything else most likely, you can always fudge ctr to ctr spacing in curves for clearance. One thing about factory curves, you never get a groink in the curve.

This subject was extensively discussed, just about 2 or 3 weeks ago. Please go to the second page on this Forum, and look for the subject "Minimum Radius" (I think that was what it was called). Lots of very good info already there.

A range of 60" thru 72 is very popular.  Many Northerns IME tend to climb the rail heads around 55" radius.

If an MTH northern derails on a 7' radius it is not the engines fault. 

I agree with Tom 60-72 will get it done and then some.  Mine are down to 60" in a few spots but most are 66" and I have no problem getting any MTH 4-8-4's around a 66".

Most curves on my mainline are are 60 and 64. The tightest mainline curves I have are 56 and 60 in one place. My largest rigid frame loco is the 4-8-4. Both the MTH and Overland versions do well into the forties. They have 70" drivers. I use Atlas flex with staggered rail joints.

The real answer to this question is as large as your space can accommodate. All the rest will sort itself out from there. What Tom, Jack, and Harry do may not work for you, unless your variables are identical to theirs. If you are one of those folks that just has to have a number, 72" radius is a pretty good default for most large locos.

Sectional curves are at best a convenience and at worst a limitation. Go with flex.

Simon

In addition to Simon's comments I ask are you planning to run big steam or are strictly diesel? 

Large steam generally *requires* larger radii in the 60-72" range because it won't track well at anything less with out modifications. 

On the other hand plastic bodied diesels are generally quite happy down to 48' radius with most capable of going around 36 or 40".  Be aware that high end brass diesels usually need larger radii around 56" or more.   So unless you are running good sized steam the limiting factor will more likely be the cosmetics of how trains look on the curves.   

I routinely run 80 foot passenger cars and PA1s or E8s on my 48" curves with no operational problems.   Some will say the overhang of an 80 foot car is excessive on such a curve but that is the price I'm willing to pay to get the operation I want in my fairly limited space.

In the end it comes down to what looks good to you.  I suggest getting a few pieces of flex track, some rolling stock and mock up some curves to see what you can live with.  (For any grammar Nazis out there - Sorry about the preposition at the end of that sentence.)

I'm jealous of those of you that car run curves that large. My train room is 12' x 16'. I'd be standing in the middle of a circle with large radius curves. 36" to 44" on a switching oriented layout is pretty much what I'm limited to.

My double track mainline curves are 68" and 72" radius. Curved yard lead is 64" radius.

Joe Foehrkolb

I just went and viewed that thread. I had missed it. Thanks.

A note on steamers and radius:

In the past I have reviewed a few MTH steamers and Weaver Diecast steamers for a now defunct magazine.    I learned that the ones I saw had SOLID side rods.   this is the big rod connecting the drivers.   On prototype locos these have a joint at each driver to allow them to articulate.   When the are solid, ie one piece, they force the front drivers to curve opposite to the rear ones in the case of the Northern described.  

All the brass models I have seen have articulated side rods and a little play in each axle as on the prototypes.   So the front and rear axles can each slide in the same direction in a curve.   This would a relatively cheap thing to do for 2 rail locos by the big mfgs such as Lionel and MTH and Weaver on their diecast stuff.   Why they ignore it is beyond my understanding.  

By the way most smaller brass steamers have no problems with 48 inch radius.   I have mikados and mountains that handle this easily.   I also have a Sunset 2-10-2 that will go around 52 inch with no problem.   I don't think I have tried it on 48 inch.