HO Locos/Rolling Stock & 18" Radius Curves

[StrasburgNut]

(I posted this thread in the Locomotives forum, but I wanted to see if I could get some info here as well.)




I do not remember where I saw it, but I read somewhere that quite a few people have no problem using 18" radius curves on their HO layouts. There are some limitations though, can't use longer wheel based cars, but they can run basic 40' and 50' cars and some decent size locos. My question is can you run GP's on 18" radius? I do not expect the dual truck/three axle GP's to make that radius, but can the dual truck/two axle GP's negotiate an 18" radius? What is the maximum length rolling stock anyone has run on 18" radius?

 

[lmackattack]

in my experince 4 axel diesel locos(GP-18 /GP-40), med steam engines (4-6-2 / 2-8-2) and 40' freight cars will run fine if there weight is correct and the track is in good shape/level. 6 axel diesels (SD40) will also run but tend to be troublesome if the trackwork is poor or has harsh elevation changes in the turn. I run 22" radius on 90% of the layout but had to use some 18" radius in my loop backs around to the lower mainline. I made shure that if there was 18" radius that it was on the flat surface and the joints were tight with no sharp edges to catch wheels. One thing I did diffrently with my layout this time was that I used the 12" long atlas sections where I needed to use 18" radius. I found that the cosistency of the 12" sections did not derail the 6 axel diesels at the joints as did the flex track in such a tight radius. All of my track was layed on foam and then a rubber road bed. The 18" radius was only used in the closet so I was able to nail to the track work down to a wood base (no track bed) to keep it from moving. I think that the Wood keeps the track level and does not let the track move around like the foam will.. long tall freight cars do not like that tight radius at all and often derail. long 4 axel passengr cars are ok if the train is not to long i.e 5-6 cars. Again if you are running a long mainline freight dont use 18". 22" is even kinda tight

The key to a good layout is the trackwork after that the rest is "easy"

 

[Selector]

You should be able to make cars up to about 70' work on 18" curves, but they will not look great. For many, this is quite problematic. It turns out, though, that even jumping up to 24" curves will not make an appreciable difference for most onlookers. I have made this observation on other forums...it takes something like an 8" difference in radius before a string of cars on them look substantially better...in other words, worth the change.

And, for 18" curves, dual axle trucks are the better way to go. You'll be stretching the design on triple-axle trucks, and may encounter so many derailments, if not of the engine then of the car behind it due to coupler swing, that you find little pleasure in the arrangement.