Small Radius curves in HO

[bob39520]

After 2 days of reading thru 9 pages of posts on radius curves ( we work at 48kb out here ) I still need some direction.  I have read that although an     0-4-0,0-6-0, 4-4-0 or a 2-6-0 will work on a 15" radius it is possable to run them on much smaller curves.  I have not been able to verify this with anybody who has tried this. Specifically, will any of the above loco's run on a 12" radius curve, assuming the loco is DCC w/sound equiped.

[lmackattack]

I would not reccomend anything less than 18" but that is just from my experince. 15" should be ok for the size engines you mention and lots of people who make logging layouts will use tight curves. the only issue you will have is that at that tight of a radius any bad sections of track or large caps at rail joints will be apperant real quick!

[WoundedBear]

The locos without a pilot truck should be fine, just make sure they have as short a tender as possible or go with tanker style locos.

Look back at the April 2008 issue of Model Railroader magazine. It features a neat little layout using an 0-6-0 and 12" radius curves. The entire layout measures 28" X 94".

Sid

[Yampa Bob]

Something else you have to consider is the distance from the rear driver to the drawbar attachment point.

On a 4-4-0, the rear driver is very close to the end of the cab and drawbar pivot. However on a 0-6-0 the distance can be as much as 1-1/2 inches.  On a tight curve, the drawbar attachment (and the cab) swing rather violently way out over the outside rail.  This can (will) actually yank the tender front completely off the rails to the outside of the curve.

It also looks terrible, and gives the engineer whiplash. I speak from experience, as I had a Mikado (2-8-2), the distance was 2 inches with a very short drawbar. I had constant tender derails on my 18" curves, even at slow speeds with added weights. 

No problem with my Connie 2-8-0, as the rear driver is only about 1 inch from the drawbar attachment point, and the drawbar is longer.

I suggest that 15" radius is the minimum for the 0-6-0, but would look and perform much better on 18".  As usual other's mileage may vary.

[Johnson Bar Jeff]

I suggest that 15" radius is the minimum for the 0-6-0, but would look and perform much better on 18".  As usual other's mileage may vary.

For myself, I'd avoid a 15" radius for an 0-6-0. None of my 0-6-0s is happy on a 15"-radius curve. They might make it around the curve--or they might not. I don't go below 18" radius for any six-coupled steam locomotive.

[Jim Banner]

Jeff, there are two tricks that may help ease your 0-6-0 around 15" radius curves.  One is to round the top inside corners of the rail heads.  This makes it easier for the flanges of the leading and trailing wheels to slip down between the rails.  The normally sharp edges tend to grab the flanges and lift these wheels.  The other is to very lightly oil your rails to achieve the same thing.  If these two together don't solve your problem, the only solution is to hand lay the track with a little more distance between the rail heads.

[Paul M.]

Interesting methods, Jim.
If you do choose to  round them, vacuum up all the metal shavings so they don't get stuck in the mechanism and harm your locomotives.

[Johnson Bar Jeff]

Jeff, there are two tricks that may help ease your 0-6-0 around 15" radius curves.  One is to round the top inside corners of the rail heads.  This makes it easier for the flanges of the leading and trailing wheels to slip down between the rails.  The normally sharp edges tend to grab the flanges and lift these wheels.  The other is to very lightly oil your rails to achieve the same thing.  If these two together don't solve your problem, the only solution is to hand lay the track with a little more distance between the rail heads.

Thanks for the interesting ideas, Jim! Though possibly the best solution is--don't use 15"-radius curves. ... 

Seriously, my 0-4-0s and my 4-4-0s have no trouble on a 15" radius. It's just the 0-6-0s and the ten-wheelers, so I just generally don't run those locomotives on those tight curves.

Interestingly, I just bought, via eBay, an 0-6-0T that was assembled from a Mantua kit that is possibly older than I am (50). The center drivers are "blind" (flangeless). I haven't yet had an opportunity to run it on tight curves, but I'm looking forward to see whether that makes a difference.

[pdlethbridge]

12" radius or less would be great for a trolley line. Curves like this, even for trolleys, were taken very slowly. How fast do you want to go?

[bob39520]

12" radius or less would be great for a trolley line. Curves like this, even for trolleys, were taken very slowly. How fast do you want to go?

As slow as I have to. Speed would not be an issue with me. Although, after some of the advise I have noted, I have dropped my plan to have a radius curve less than 15'' thru a tunnel.

[Johnson Bar Jeff]

12" radius or less would be great for a trolley line. Curves like this, even for trolleys, were taken very slowly. How fast do you want to go?

As slow as I have to. Speed would not be an issue with me. Although, after some of the advise I have noted, I have dropped my plan to have a radius curve less than 15'' thru a tunnel.

I think that's a wise decision. A derailment on a 15"-radius curve inside a tunnel would not be fun. 

[bob39520]

Look back at the April 2008 issue of Model Railroader magazine. It features a neat little layout using an 0-6-0 and 12" radius curves. The entire layout measures 28" X 94".

Thank you for the info. I just got the April copy and it was exactly what I was looking for. This gives me new hope. Now if I could just find an 0-6-0 dcc/sound I would be in high cotton.

Again, thank-you, I appriciate the help.

Bob