I’m in the process of building an 11x15 HO layout with staging/storage on a lower level. Construction of the lower level is in process and I’m using a 2 percent grade which is the same as the one I previously had on this layout’s earlier version.
With one exception, the curves on the incline are 30 - 32 inche radius. That one exception is a near 3/4 circle that will probably end up being 26 inch radius - although it could be closer to 25 1/2 inch. In the earlier layout this was no problem, as the F, GP, and RS units could easily handle it.
However, I now have a BLI ATSF 4-8-4, 2-10-2, 2-10-4, and a whole lot of Walthers light and heavyweight passenger cars - and I am concerned if they will handle the smaller radius curve.
Soooo, what is your experience with the above locos & cars? Will they work for me, or are they destined to live on the main level - or end up in a display cabinet? Or, is it back to the drawing board (not an easy task at this juncture)?
Thank you,
Mobilman44
PS: Yes, I could lay the track and test them myself - but I might be too easy on the results and end up living with the problem rather than resolving it now (during construction).
The Walthers cars should be good down to 24", but the odd one won’t…it’s a fact. In fact, I wouldn’t think of operating them at that radius at speeds above a yard walk. The odd one needs some tweaking, often just paring back some plastic behind the steps or under the frome, maybe fixing the mounting of the truck. If you have honest-to-goodness 25.5" radius curves, you should be fine entirely. You’ll just build that much more distance between you and the odd derailment as you extend your radius a half inch at a time. So, my advice would be to work hard at doint that.
As for your engines, they would be good down to 22", but it could be really iffy below that. At 25" or more, you will be fine. I have similar ones (BLI Niagara, the PRR J1 2-10-4 with looooong 1000-mile tender, and now the Brass Hybrid UP-TTT-6. Even the J1 can do 22" curves, but it sure as heck don’t like 'em.).
I would be interested in your track plan. I’m starting work on a modified around the walls shelf type layout and have always considered a lower level for staging and general run-around.
Using transition curves (of ever increasing radius) at the beginning and end of the curve would be helpful to reduce the “jump” from straight to curved. Train operation and appearance will benefit. If necessary, it would be better if you reduced the curve to 25 inches to give room for the transition. This would provide a 1/2 inch of lateral distance to give room for the transition. The transition should be about 2 car lengths long, starting 1 car length before where the curve would have started without the transition and 1 car length beyond that point. I recommend you use transition curves everywhere, not on just your sharpest curves.
I’m big on transition curves, and have used them since I went to flex track in the early '70s. This one curve will have a decent transition on the one end, but the other will have a minimal one - due to lack of space. The good news is the trains will be going fairly slow, so I “should be” ok.
My experience is that if there is going to be trouble it will be with the Walther’s heavyweight cars. However, I have to confess that I’ve never gone into 26" territory. I believe the tightest I’ve taken mine is 28". I modified every single heavyweight to give the trucks more swing.
modifing trucks, do you mean the front and rear trucks? I’m trying to learn about this type of changes to steam locos before I start building my dream layout, thanks
I hope I don’t misspeak for Terry, but he means the trucks under the heavyweight passenger cars. They are only able to swing so far in either direction, but there is always some variance from car to car, as I alluded to in my first response above. The trucks will make contact with “something” that they wouldn’t normally on broader curves. (Remember, we’re talking about the stated minimum radius for Walthers heavyweights). This might be the backs of the steps, contacts for electric lights inside the car, appliances on the under-frame, or maybe even some plastic flashing not removed when the various items were removed from the molds. Once you move into curves approaching 26", you should have no problems.
Your engines will be fine on anything above 23" curves, even at some speed. As Terry says, if anything gives you trouble, it will be the heavyweights…but not on 26" curves. At least, much less likely than on 24".
One thing we haven’t mentioned are the diaphragms between the cars. They, too, can be a big factor in tracking on the minimum radius curve. They may not compress sufficiently to let the cars stay on the rails. Walthers claims they should be fine, but some have encountered the odd problem with the diaphragms.
In regards to the Walther’s heavyweight cars, I believe there are details in the instruction sheet that come with the cars that explain how to trim the center sill to allow the cars to negotiate tighter radii. I would have to look to verify, or maybe someone could verify this?
I can’t imagine the factory-provided diaphrams of Walthers heavyweights or their Branchline cousins causing problems since the diaphrams are no where near touching when the carss are being pulled. I find it rather disturbing to watch the gaps between these cars… Realistic-looking diaphrams which provide continual connection are likely to limit the cars’ minimum radius. Has anyone tested the minimum radius of these cars with AHM diaphrams?
Mark, they certainly touch in my case going around a 24" curve at one throat to my yard. They may have a gap when on something wider, say 32", and of course when on tangents, but in the case of their stated minimum radius they do make some contact.
Thank you all for your input - and the very good news! I was especially worried about the BLI locos making it down to the staging area, but you have assured me it should be OK. The passenger cars should also be OK, or need minimal “adjustments” to clear the curve.
In my original scale drawings, I had a 28 inch curve in this area (as opposed to what will likely be 25 1/2 - 26 inch. The scale drawing was accurate - but - ignored the fact that 2x2 legs would be around the perimeter of that area. In short, I screwed up!
Ha, my old drafting teacher (Lane Tech High - Chicago - class of 2/62) would be slamming his scale rule on my desk and use all the ink in his red marker if he were here!
Could you use a bracket and cantilever that item supported above it? Make the 2X2 start at its top end below the ramp area. Then you could have your wider curve. What I am suggesting, in other words, is to displace the leg, or do some modification to allow the wider curve…unless it is moot because of your findings.
I have a BLI C&O 2-10-4. The instructions recommend 24" radius, but it will go thru a 22"R curve but with some complaining and slowing down as the drivers try to bind up. I had no trouble on my last layout running Walthers cars on 28"R curves but no chance on 22"R, even the 60’ cars wouldn’t do it…but I never tested anything in between those two.
I would recommend a “real world” test, go to the LHS and get some Kato Unitrack at 26"R and some 14" straights and a terminal track, and do some tests and see what will work and what won’t.