Will a Pacific, Consolidation, or Mikado handle a #4 turnout OK? I’m planning on using (1) on my mainline as it enters my yard. I’d assumed I’d be OK with a strict speed limit through the turnout, but if that’s not enough to avoid trouble I can try to find an alternative (actually, I don’t know what I’ll do, but I’m trying to be an optimist). I’d appreciate any advice. Thanks.
Rick Krall
Rick, it depends on the model and how “loose” it is. Many locomotives are designed to operate on very tight curves, either with blind drivers or with sloppy axles that can slide as much as 1/8" from centre. Number 4 curves are very tight, and I cannot say for sure but I don’t think my BLI Pacific would go through one because the axles are fairly tight and the drivers on most Pacifics were in the higher diameter range for fast hauling…at least, the K4 had them.
A Mikado would probably be in the same bit of difficulty due to the added driver, even though those on a Mike were often smaller. My Trix Mikado will go around curves in the 18" range, so it may just do a #4. The NMRA standards says that compliant #4 turnouts have closure rails at 15" radius, and this single fact leads me to suspect that you won’t be successful if for no other reason than that commercial turnouts are rather sloppy, and a sloppy #4 is not going to help a large locomotive get through it when its geometry is meant to be insufficient in the first place; it’ll make things worse!
Something like an Atlantic 4-4-2, or a smaller Mogul 2-6-0, maybe a smaller Prairie 2-6-2, or an American 4-4-0 might be okay. If you can test to make sure at a hobby shop, that would be the best thing to do.
Probably but I wouldn’t want to go through a pair of #4 crossovers with one.
I’ve got a 4-6-4 Hudson from BLI. It is happy with 18-inch curves and Atlas snap-switches. I found a few spots where I had to touch up the trackwork when this engine first arrived at my layout, but the problems were with imperfect tracklaying, not the engine.
This engine has a two-position tie-bar with its tender. It can’t be in the “close-coupling” configuration or you’ll have trouble on 18-inch curves.
It depends on whose #4 you are using. Atlas #4 is actually a #4.5, some other manufacturer’s also have a slightly larger #4.
Also, some engines will take the 15" radius curve that a #4 turnout built to NMRA specs call for. It depends on your locomotive wheel base. Small drivers are usally a shorter wheel base. If the center drivers are blind (no flanges) then you can get through a tighter curve. If there is enough side play in the drivers you may get through.
If you can, using a #5 would be better and should be no problem no matter whose Pacific, Consolidation, or Mikado you use. Otherwise you will have to experiment with your engines and your #4 turnout.
Enjoy
Paul
Really depends on three factors, somewhat interconnected:
I have a bunch of six- and eight-coupled tank locos that will pull prototypical trains around 400mm (14" minus) curves all day, and a couple of early plastic 4-8-4s that will take an Atlas snap-switch but look seriously ugly doing so. (Those 4-8-4s are so sloppy that any master mechanic worthy of the title would relegate them to the back shop for immediate axle box inspection.) I also have one tank loco with a four-wheel trailing truck that has WAY too much rear overhang to stay coupled to anything on a #4 turnout’s curved route. On anything less than a 22" radius curve the car behind the bunker would be in serious jeopardy.
Chuck (modeling Central Japan in September, 1964)
Thanks to all; what great, helpful responses. I now know my options and I’ve learned what a blind driver is and about the 15"-radius divergence. I appreciate your responses.
Rick Krall
I have an Athearn Mikado that has no problem going through an Atlas #4 Code 83 turnout. My Bachmann Ten Wheeler and AHM Mogol are also fine with this turnout, although it was necessary to put power pick-ups on the two tenders.
Ray
As an earlier poster said, most commercial #4 turnouts do not have a 15" closure radius. The Atlas #4 is really a #4.5 with a 22" closure radius. The Walters/Shinohara #4s are lengthened beyond the NMRA RP, and have greater than a 15" closure radius - probably close to 18". Peco uses a constant radius in their turnouts, except the American style code 83.
Hope this helps
Fred W
Actually, the Onion Specific regularly got their Big Boys to negotiate #4 switches; of course by the time it finished straightening out the curves it had converted the #4 switch to a #20 switch.
On a serious note, I had five Cary/Mantua Mikados and three Cary/Mantua Pacifics in my HO Scale stable and, although I never had any #4 switches anyplace on any of my layouts, I did have #6s which did not give me any operational problems; however, there was a pronounced lurch of the lokes when they went into the switch and they looked just a little cumbersome going through a switch that sharp. As I said, I never had any #4 switches but had I had them I think that these Mikes and Pacifics would probably have gone through them but I would have kept the speed to a crawl doing it.