Is there any danger of .015 wide frog rail gaps in a Fast Track turnout closing up from rail expansion? Seems the close spaced PC tie solder joints on the frog and adjacent rails would prevent the gaps from closing and Fast Tracks instructions don't mention filling the gaps after cutting, but...........
Thanks, Peter
It depends on who you talk to. Some folks swear that you need to fill that gap with plastic (or Fast Tracks sells cut plywood "plugs") as the track will expand and close them.
That would seem to depend a bit on the environmental conditions of the layout. My previous layout was in the basement of an old home in the North East, water ran down the granite block walls on occasion, and for the two years I had it up, I didn't have any problems with them closing (I did not fill them).
My current layout is now in a climate controlled apartment, with minor fluctuations in humidity and temp. I haven't filled mine, and have (not surprisingly) had zero problems.
Like you, I'm suspect that soldered rails will move like their spiked counterparts, it would seem that the solder join would have have to shear, or the section flex if the rail were to expand in that manner. That doesn't mean that it can't, mind you, but I question it as well.
In the end, it only takes a few moments to fill them, perhaps for safety's sake its worth it. I may have regrets if I have to track down a short.
I'm trying to model 1956, not live in it.
So long as the soldered joint holds, I don;t much see how the gap can close up. The rails don;t expand and contract much - let's not start another of thsoe threads, but the coeffeicient of expsnasion for nickel-silver is extremely low and requires a HUGE temperature change. Maybe if your layout is in the attic and it gets to 120+ there in the summer and you just don;t ever go in there.. anyway, the rails on the outside, if they expand, make the frog gap GREATER, while the cut rails for the frog are trying to close the gap - so you are generally safe. If your sub-structure contracts enough to force the gaps closed, the outer rails will likely be kinked as well.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I used a jeweler's saw as Tim suggests in his videos, and made eight turnouts. No, I also built two custom ones the same way, so 10. In six years, not one of them has shorted.
Crandell
It seems then that barring extreme fluctuations in temperature and or humidity filling the Fast Tracks frog gaps with Fast Tracks wooden "Stop Gaps" or plastic shims would be of more aesthetic value than necessary to maintain the gaps. I can see that filling the gaps and dressing the shim of choice would be a whole lot easier before installing the turnout. I think my reluctance to filling the gaps isn't so much the time involved, but the likelihood of marking up the tops of these beautiful turnouts when dressing the shims. I also tend to think that once the rail is painted and the turnouts ballasted the gaps won't stand out.
I would have thought that the gaps could not be closed by rail expansion either. However, my layout is in a Southern California garage. Some of the track I laid during winter months exhibited lots of expansion in hotter summer months. The main problem was insufficient clearamce between the rails of the turnouts and the adjoining lengths of flex track. When the long lengths of flex track expanded, the pressure against the rail ends of the turnouts was enough to close a few of the frog rail gaps. I guess the PC ties are fairly flexible after all. However, simply cutting the gaps again with a razor saw restored sufficient clearance and electrical isolation.
Hornblower
If in doubt, insulate. Then you'll never have to worry about them.
My layout resides in a non-climate-controlled Mojave Desert garage. 120+ degree (F) temps aren't merely possible, they come with the territory. I have had rail expansion and rail creep close uninsulated gaps (and kink rails where I failed to leave sufficient gap when laying track in more comfortable temperatures.) A bit of plastic, or a droplet of model cement, will prevent electrical misadventures.
Incidentally, before anyone starts that old, "It isn't the temperature, it's the humidity," chant, two facts:
Chuck (Modeling Central Japan in September, 1964)
As I have posted a number of times over the few years I have been a member here, Code 100 nickel silver rail expands about 1/4" over a 100' length with a temperature change of 30 degrees F. Once a bunch of really tight gaps squeeze shut for any reason, humidity in the wood supporting the rails or temperature changes, it won't be long before 1/4" is used up unless you have a few gaps over that 100' that are in the 1/16" range. So, while humidity is the greater problem if you have wooden benchwork, temperatures will also affect a rail system where there are few, tight, or no gaps if the space isn't controlled for temperatures.