is 12.5" radius too small for N scale?

[Trainsk8]

I have a Z scale layout on a 25"x72" table that i got from my great uncle. It runs very poorly, you have to push the old Marklin locos all the time. The wiring is also old and complex. I plan to tear it down and build an N scale layout on it.  The maximum radius I could have would be 12.5".  I hope to run SD70s and other 6 axle locos, if those locos couldn't run on 12.5" i would use 4 axle jeeps instead. The rolling stock i would like to use if possible would be intermodal, coal trains, and cars found on mixed freight. I have not had any experience with N scale, please help me.

 

[Anonymous]

Most N scale equipment will run on 12.5 radius. You will find some that wont. BTW, the radius is to the CENTER of the track. With 25" wide table, you need 1/2" MINIMUM on each edge and 26" outside to outside on the track for a 27" wide table. For a 25" wide table, radius is going to be more like 11.5". Some equipment will have a problem with that small a radius, but you will find sufficient equipment that doesnt. Its not ideal, try and go with wider curves if at all possible.

[pcarrell]

Longer cars and 6 axle loco's would be a tough one to get to operate reliably, and they'd not look their best , thats for sure.  I go for the 4 axle loco's and some shorter cars.  You'll not have the headaches of reliablity (the problem you already have with the current layout) and it'll look better too.

[stebbycentral]

Actually back in the good old days when N-scale was new the standard radius for Atlas sectional track was right around 11 inches.  The radii on the pieces that came with turnouts measured out at 19 inches, and that was the biggest radius available in sectional track.  Even today standard Bachman sectional track is about a 12 inch radius.  But today of course you can get Kato sectional track that goes up a 36 inch radius.  Boy, I wish I'd known about that stuff when I was constructing my current layout.

[pcarrell]

But today of course you can get Kato sectional track that goes up a 36 inch radius.

And Atlas code 55 sectional track up to a 71" radius, but I don't think our friend here is going to find much use for that.

Back in the early days of N scale, 11"r was considered "standard", but then the equipment that ran on it was very crude.  With the refinement of equipment came a necessary refinemnet of other areas as well.  Curves became more broad and the equipment became more refined.  Tolerences became tighter and broad curves with easements became more necessary, and so on.  Today we have a wonderful assortment of very fine equipment from which to pick, but it has some requirements.  Long wheelbase loco's demand larger curves, and that's just the way it is.  That's OK though.  It's the same in every other scale.  Besides, I'll take a great running, fine looking loco any day.  And that great technology will trickle down to the smaller loco's too.  Heck, it already has in a lot of cases!

[dad1218]

  The SD-70 might go around an 11" curve, there probably will be some overhang. Don't know about the intermodal cars because I don't have any. I have 12 3/8 radius Kato track, my SD-35 goes around it alright, but my passenger cars have a good bit of overhang. If your carpentry skills are up to it and you have the room, I would widen the table 6-12".

     Have you decided on a track to use. I like the Kato, but when I get to where I can have a room for a layout I am planning on code 55 flextrack.

                      Gary

[Vail and Southwestern RR]

This page: http://www.nmra.org/standards/rp-11.html

has the NMRA Recommended Practices for radius/scale/equipment.  Based on that, SD-70s and 12.5 inch radius don't really mix.  That being said, most N scale eqipment will operated on that radius, it just won't neccessarily look good doing it.  Every bit you can add will really help.

 

[ft-fan]

From what I've read on this forum and other places, you can probably run the loco on about 12" radius. Since you are going to be starting over, you may want to consider just getting a new table-top. You don't say how it is constructed, if it is just a plywood table on some kind of base, a sheet of plywood should be pretty cheap. Most home centers will even cut it to size for you, if you only need a couple of cuts. You might think about going to a 36" x 72" table-top, this will let you run 16"-18" radius curves, which should give you absolutely no problems with any of the cars or locos you mentioned. And it will only add less than a foot of width to what you have now, so hopefully that would fit in your room.

FT

[Mailman56701]

  In my experience, I wouldn't go less than 15" for six axle locos in n scale.  19 as a min. is even better if possible.

  They'd run on less than 15, but they'd look terrible, plus the first car behind them would most likely be pulled off the track by the loco's coupler overhang.

[Wdlgln005]

You may be best off sticking with Zscale. Check out the new MTL track & rolling stock. Perhaps you won't need to scrap everything. AFAIK the new MTK track follows the geometry of the Marklin track, so if they can be cleaned to work, you may salvage the Marklin turnouts.

The new Z GP35's & GP9's from MTL are fine locos. Soon, they will produce an SD40 that can share necessary components with a E unit. check out any store that sells Hallmark ornaments for the Lionel American Freedom Train cars & locos. The trucks & wheels can be modified to run on Zscale track! The PA can be swapped with a GP chassis to make it powered! This may get even easier in the future when the SD40 mech becomes available.

Check out the Zscale Forum on TrainBoard. You should also find some Zscale video via Youtube & other websites. + 

[spidge]

I would clean the track on the Z-scale layout and tune it up before writing it off. As suggested earlier, try a newer unit. Most of the problems will stem from dirty track and loco wheels. Use the gleam method on the track and look closely at the loco treads. Make sure they are not full of pits as the pits would constantly fill with gunk and spread it around.

The 12.5 inch radius would support four axle units well but anything six axle will give you headaches. 16 or higher for the six axles would be suggested and if you desire large steam then 18 would be minimum. A word about minimums, a bit of this is personal. Even though the manufacturers say they run on small radii does not mean you will like it. Mu one steam loco(n-scale) grinds around my 16 inch curves.

[Zandoz]

Here would be my compromise.........

First I'd put a 2" slab of foam on top the existing table, with a minimum dimension of 29x72.  To preserve the edges of the foam and to make a plummit guard, I'd glue a band of 1x4s or other trim molding around the perimiter.

For track, I'd go with Kato Unitrack, and instead of sticking with fixed radius curves, I'd start each end of the curve with one of the 28-1/4" radius sections.  Those large radius sections are directly replaceable with Unitrack #6 turnouts, for siding/interchange/expansion tracks going off into the corners.  Also, those initial larger large radii sections will act as pseudo easements, to make the tight curves less harsh.

Below is a sample starting point loop I worked out following this philosophy.  The sample uses a minimum 12.375' radius on the outer loop, and 11" on the inner loop on a 72x29 footprint.  Personally, I'd try to stretch it to 32x74 and go with 13.75"/12.375" minimum radii.

[pcarrell]

plus the first car behind them would most likely be pulled off the track by the loco's coupler overhang.

With body mount couplers this might be true, but since most all N scale equipment uses truck mounted couplers this is basically a non-issue. Thats why N scale uses the track mounted ones.....so we can run the sharper curves.

[Mailman56701]

plus the first car behind them would most likely be pulled off the track by the loco's coupler overhang.

With body mount couplers this might be true, but since most all N scale equipment uses truck mounted couplers this is basically a non-issue. Thats why N scale uses the track mounted ones.....so we can run the sharper curves.

  Well, one of the premier N scale suppliers, Kato, uses body mount couplers on many of their locos and stock, including the original poster's loco of choice, an SD70.

 

 

[Mailman56701]

Here would be my compromise.........

First I'd put a 2" slab of foam on top the existing table, with a minimum dimension of 29x72.  To preserve the edges of the foam and to make a plummit guard, I'd glue a band of 1x4s or other trim molding around the perimiter.

For track, I'd go with Kato Unitrack, and instead of sticking with fixed radius curves, I'd start each end of the curve with one of the 28-1/4" radius sections.  Those large radius sections are directly replaceable with Unitrack #6 turnouts, for siding/interchange/expansion tracks going off into the corners.  Also, those initial larger large radii sections will act as pseudo easements, to make the tight curves less harsh.

Below is a sample starting point loop I worked out following this philosophy.  The sample uses a minimum 12.375' radius on the outer loop, and 11" on the inner loop on a 72x29 footprint.  Personally, I'd try to stretch it to 32x74 and go with 13.75"/12.375" minimum radii.

  Good points.  Have you considered using the 19" curves, instead of the 28.25 ones ?

[tgindy]

How about a Sunday drive to the Atlas website?

• Code 80 N Scale => http://www.atlasrr.com/Trackmisc/ncode80.htm 
• Code 55 N Scale => http://www.atlasrr.com/Trackmisc/ncode55.htm
  

Sectional curved track radius is on 1.25" centers.  Note the greater selection of Code 55 which is also much closer to prototype in appearance.

The intent of commercial track is its "plug 'n play" user-friendliness so that things just work.  This may be a simplistic observation, but what sectional track Atlas does make available is instructive.

[pcarrell]

plus the first car behind them would most likely be pulled off the track by the loco's coupler overhang.

With body mount couplers this might be true, but since most all N scale equipment uses truck mounted couplers this is basically a non-issue. Thats why N scale uses the track mounted ones.....so we can run the sharper curves.

  Well, one of the premier N scale suppliers, Kato, uses body mount couplers on many of their locos and stock, including the original poster's loco of choice, an SD70.

Point well made!

I forget that sometimes since I don't have any on the "D" word on my layout.

[Vail and Southwestern RR]

plus the first car behind them would most likely be pulled off the track by the loco's coupler overhang.

With body mount couplers this might be true, but since most all N scale equipment uses truck mounted couplers this is basically a non-issue. Thats why N scale uses the track mounted ones.....so we can run the sharper curves.

  Well, one of the premier N scale suppliers, Kato, uses body mount couplers on many of their locos and stock, including the original poster's loco of choice, an SD70.

 

Our Kato AC4400 came with an extra set of long shank couplers.  They don't look as good, but better than throwing the train on the ground!

 

 

[Mailman56701]

plus the first car behind them would most likely be pulled off the track by the loco's coupler overhang.

With body mount couplers this might be true, but since most all N scale equipment uses truck mounted couplers this is basically a non-issue. Thats why N scale uses the track mounted ones.....so we can run the sharper curves.

  Well, one of the premier N scale suppliers, Kato, uses body mount couplers on many of their locos and stock, including the original poster's loco of choice, an SD70.

 

Our Kato AC4400 came with an extra set of long shank couplers.  They don't look as good, but better than throwing the train on the ground!

 

 

  Yeah, I've had to put those on all my Kato locos when running their coalporters.  Without them, 19 is the min. radius, with them 15 is, and in my situation, I need to use those 15's in some areas.

  Folks say the Micro-Trains conversion solves the problem, but I saw no performance difference, (first coalporter pulled off the 15 curve), so I just put the long shanks on.

  I'm a big fan of Kato stuff, but their lack of mentioning/acknowledging this problem pissed me off

[Zandoz]

Here would be my compromise.........

First I'd put a 2" slab of foam on top the existing table, with a minimum dimension of 29x72.  To preserve the edges of the foam and to make a plummit guard, I'd glue a band of 1x4s or other trim molding around the perimiter.

For track, I'd go with Kato Unitrack, and instead of sticking with fixed radius curves, I'd start each end of the curve with one of the 28-1/4" radius sections.  Those large radius sections are directly replaceable with Unitrack #6 turnouts, for siding/interchange/expansion tracks going off into the corners.  Also, those initial larger large radii sections will act as pseudo easements, to make the tight curves less harsh.

Below is a sample starting point loop I worked out following this philosophy.  The sample uses a minimum 12.375' radius on the outer loop, and 11" on the inner loop on a 72x29 footprint.  Personally, I'd try to stretch it to 32x74 and go with 13.75"/12.375" minimum radii.

  Good points.  Have you considered using the 19" curves, instead of the 28.25 ones ?

Using the 19" curved sections would preclude replaceability with the #6 turnouts...the 19"ers could be replaced by #4s, but probably not good on the main.   Also, and Kato's #4s have a rep for needing attention to work right in many cases.

[Mailman56701]

Here would be my compromise.........

First I'd put a 2" slab of foam on top the existing table, with a minimum dimension of 29x72.  To preserve the edges of the foam and to make a plummit guard, I'd glue a band of 1x4s or other trim molding around the perimiter.

For track, I'd go with Kato Unitrack, and instead of sticking with fixed radius curves, I'd start each end of the curve with one of the 28-1/4" radius sections.  Those large radius sections are directly replaceable with Unitrack #6 turnouts, for siding/interchange/expansion tracks going off into the corners.  Also, those initial larger large radii sections will act as pseudo easements, to make the tight curves less harsh.

Below is a sample starting point loop I worked out following this philosophy.  The sample uses a minimum 12.375' radius on the outer loop, and 11" on the inner loop on a 72x29 footprint.  Personally, I'd try to stretch it to 32x74 and go with 13.75"/12.375" minimum radii.

  Good points.  Have you considered using the 19" curves, instead of the 28.25 ones ?

Using the 19" curved sections would preclude replaceability with the #6 turnouts...the 19"ers could be replaced by #4s, but probably not good on the main.   Also, and Kato's #4s have a rep for needing attention to work right in many cases.

  Ah, ok, thanks, makes sense.   I was just thinking of space savings with the 19's.

[R. T. POTEET]

I have a Z scale layout on a 25"x72" table that i got from my great uncle. It runs very poorly, you have to push the old Marklin locos all the time. The wiring is also old and complex. I plan to tear it down and build an N scale layout on it.  The maximum radius I could have would be 12.5".  I hope to run SD70s and other 6 axle locos, if those locos couldn't run on 12.5" i would use 4 axle jeeps instead. The rolling stock i would like to use if possible would be intermodal, coal trains, and cars found on mixed freight. I have not had any experience with N scale, please help me.

No, its not too small; in fact, it is too big - at least it is too big for your 25 inch wide table. Those 12.5 inch radius curves are  going to overhang your table edge by the gauge of track plus the (outside) length of ties; this is an open invitation for your train to plunge into the depths of bottomless canyon. Assuming a tie length of eight feet - ties come in eight feet, eight and a half feet, and nine foot lengths on the prototype; I don't have the slightest idea how long the ties are on commercially available track - you could get by with a radius of 12.2 inches but at the end of the curve your ties are going to fit flush with the table edge and that is going to look just a little bit stupid.

You should probably allow a one inch space between your table edge and your end of tie; this one inch gives you space for the slope of your ballast plus what is termed a scenery belt. This one inch scenery/ballast belt will give you a radius of 11.2 inches.

Now to address your equipment portion of your post. An 11.2 inch radius curve is a sharp curve; model manufacturers engineer most of their equipment to negotiate curves of that radius but you are going to be presented with a severe overhang on anything in excess of fifty feet in length. This includes six-axle road switchers and intermodal cars. They'll go around that radius curve; they are just going to look like aitch doing it.

It is nice that your great uncle conveyed this Z Scale layout to you but if you have N Scale aspirations you probably would be better served to junk the thing and build you an N Scale layout on a 30 inch by 80 inch hollow core interior door. These hollow core interior doors are very popular for N Scale layout platforms and they are readily available at home improvement centers.

And as a matter of information, the 4 axle road switchers manufactured by EMD are Geeps; Jeeps is that junk manufactured by Daimler-Chrysler and is referred to as The auto mechanic's best friend!!!

[Trainsk8]

thanks everyone, but the thing is is that i have an HO scale layout taking up my whole room which is 14'x20' layout. I just want to use the table for a small layout.thanks