18" Radius ?

[tford]

I am using all Bachmann E-Z track on my layout. my question is this-- will 18" radius curves work with all sizes of rolling stock and engines?

[Chris350]

I am using all Bachmann E-Z track on my layout. my question is this-- will 18" radius curves work with all sizes of rolling stock and engines?

Short answer is no it will not work with all sizes.  Perhaps if you told us what you were planning on running we could be more specific as to how well it would run and how odd it might look.

[ABC]

Nope, for example the new dda40x needs a minimum 22" radius, most 89' and 86' rolling stock need a minimum 22" radius, many passengers cars require a minimum 22" radius and some require a minimum 26" radius, 4-8-8-4s (big boys), 4-8-8-2s (cab forwards), 4-6-6-4 (challengers), triplex's, require a minimum 22" radius, many 6 axle diesels require 22" radius, articulated auto-carriers and intermodals require a minimum 28" radius, and I could go on and on....
Basically here is what you should be able to run, rolling stock that is 60' or shorter (or possibly greater depending on the coupler length & other factors). Steam locos in these configurations....0-4-0, 0-4-0T, 4-4-0 (american), 0-6-0, 0-6-0T, 2-6-0 (mogul), 2-6-2 (prairie), and some 4-6-2 (pacific) and 4-6-4 (hudson) locos. And any 2 axle diesels (critters) or trolleys/streetcars, any 3 axle diesels (WDT plymouth), any 4 axle diesels.

[ABC]

For example from Bachmann's website:
EMD DD40AX¹ CENTENNIAL - HO SCALE
Item Nos. 62101, 62102, 62103, 62104
MSRP:$125.00
A giant from Bachmann's past gets the modern treatment with updated electronics and detailing.
Minimum 22" radius curves required.
features include:
      DCC-equipped for speed, lighting and direction
      dual mode NMRA compliant decoder with eight-pin plug
      two skew-wound motors with four flywheels
      twelve-wheel drive
      LED headlight (constant lighting)
      weathered air intakes and exhaust stacks
      numerous detail parts
      scale 42" wheels with RP25 wheel contours
      designed for aftermarket sound installation
      E-Z Mate® Mark II couplers
1 Notice how it is incorrectly called a DD40AX instead of DDA40X which technically is the correct name.

[Jim Banner]

For some locomotives, 18" radius is grossly under size.  Some tests a few years ago showed that a brass Selkirk would not run on anything less than 30" radius.

Jim

[jbsmith]

18 inch works just fine with MOST things.
Locos-Diesel up to a SD-40/45, Steam up to a 2-8-4 or 4-8-2.

Any thing larger go with 22 inchers or greater if your available space permits.
if you are using a 4x8 sheet of plywood or 5x9 pingpong table, then
22 inch is about the maximum that will fit.
and on a 4x8,,22 inchers fit just barely, if a derailment occurs,Murphys Law dictates that  the train will go over the edge and hits the floor.
Rarely will the train fall to the Inside of the table.[this only happens when
Murphys enforcers are off on a coffee break]

Rolling stock, up to say..a 56 ft hopper. anything larger figure 22 inch.

Most Passenger cars like Heavyweights,Streamliners, Modern, ect, figure
22 inch.
Old time passengers cars, like the ones made by Roundhouse that are
34ft or 50ft will be ok on 18 inch.

[ABC]

18 inch works just fine with MOST things.
Locos-Diesel up to a SD-40/45, Steam up to a 2-8-4 or 4-8-2.
Rolling stock, up to say..a 56 ft hopper. anything larger figure 22 inch.
Most Passenger cars like Heavyweights,Streamliners, Modern, ect, figure
22 inch.
Old time passengers cars, like the ones made by Roundhouse that are
34ft or 50ft will be ok on 18 inch.

You're in agreement with me on length of rolling stock & passenger cars, but not with engines. But I'd say most heavyweights, streamiliners, modern, etc... require at least 24" radius, and some Rapido ones I have require 26" radius. But most cheap passenger cars only require 22" radius because they are not built to match the prototype, but built to run on 22" radius (which isn't necessarily a bad thing because many people can't fit any larger than 22" radius or don't want to have to use flex track).
My SD-45s won't run on 18s, they also need 22" radius.
My 4-8-2 Heavy Mountain and 2-8-4 berkshire won't run on 18" radius, I tried it. I tried with my flex track and it requires what would figure to be 21" radius, so if using sectional track that would mean you'd need 22". Also, my 0-8-0 requires 22", as does my recently acquired 2-10-4 (know as Selkirks in Canada and Texas' in the states).

[lmackattack]

from my experince if the mfg says a large loco will make it around 18" they have stretched the truth. in a perfect world in may work flawless but not on any of the layouts I have run on, including mine. Yes I can get my SD7 around 18" but try with a SD40-2 and its a diffrent result. same with large steam. My mountian does ok on 18" but 22" is alot better put a large berkshire on and it wobles and scrapes around the rails. I think that the mfg does build locos with intenteions to make it around 18" but real life experince says your safer going to the next larger radius than the MFGs sugested minimum.

Look at this chart it may be helpfull to some about the NMRA standard radius vs loco size. I have violated a few standards but for the most part all my locos stay on track with my 22" radius

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

[tford]

Thanks again guys for all the info!

[bobwrgt]

If 18in is all you have don,t worry. I have one main line with 22in and one with 18 in Life Like Power lock track.
On the 18in i can and do sometimes run the Following with no problems and at all speeds.  You just need level track that is layed well.

SD40-2 Bachmann and BLI and Athearn
Bachmann Heavy mountain  3 of them
Bachmann light Mountain
Kato SD70M and three Protos Sd50 and 60m
IHC Mountain and Hudson
SD45's Bachmann and Athearn
Proto SD7/9
Kato C44-9w, Bachmann C40-8,c40w
Atlas 8-40cw,c30 and U33c

You may have to put a long shank coupler on the first car in the train to allow for the swing.
I will say the 6 axle engines look better on larger curves but if you just want to have fun you can get all of them to work.

Bob

[artkent]

The following WILL RUN on 18" radius, may not look good but will run:
UP 4000 4-8-8-4 BIG BOY..Rivarossi 5412
UP 3716 4-6-6-4 CHALLENGER...Rivarossi 5456
N&W 118 & 120 4-8-2 HEAVY MOUNTAIN...Bachmann 84203 & 82504
SRR 1401 4-8-2 LIGHT MOUNTAIN...Bachmann 81602
ACL 8003 2-10-0 RUSSIAN DECAPOD..Bachmann 81703
GN 2100 2-10-2 SANTA FE...IHC 2340
And anything smaller.
The only one that I've found not to run is the N&W 611 J Class 4-8-4... Bachmann 82103, it required milling to allow more travel for rhe trucks and the draw bar had to be lengthened 1/8".
The old N&W J Class 600... Bachmann 41-0658-A4 runs fine on 18" R.
Diesels later.
Art

[ABC]

You're just asking for trouble with some of those. If you do run large locos like a challenger or big boy or northern be sure you have enough clearance around the track so you don't clip/ take out any scenery or perhaps locos on adjacent tracks with the overhang. Just picturing a 4-8-8-4 on 18" radius makes me cringe, but if you're determined to run a big boy on your 18" radius layout far be it from me to hold you back. Don't be complaining when you forgot to compensate for the overhang and have to put all your trees and utility poles back up or when it falls off the table due to an imperfection in the track work or due to an unforeseen collision.
Its not that hard to buy 22" radius atlas snap track, heck they even have 24" radius snap track in atlas code 83. You'll be happier when you seem to have less problems than before, but don't know why. As a general rule the larger the radius the less problems you will have as a whole. Use the biggest radius and turnouts you can fit on your layout if at all possible.

[DaveMFnC]

MY spectrum 2-8-0 happily runs on 15" radius.