Snoq.
A couple of things that I forgot to mention regarding the Nickle Plated track.
1. I have been told that it is the LGB Brass Track with Plating on it so the electrical conductivity is the same as BRASS.
2. I read in one of the threads that the OXIDATION that forms on the Nickle Plating is much more conductive to electricity then the OXIDATION that forms on the Brass Track.
I would say that the Nickle Plated Track is the BEST of both worlds, but is just my opinion. Again I say Good Luck and stay focused, Ron
Ok, I'm going to dump a lot of data on you (AKA facts) and then give my opinion of the data at the end as it pertains to your application. I assume that 6061-T6 aluminum alloy is not in consideration here although I think it would be an excellent choice as the 6061-T6 is the same alloy used in the tail sections of Boeing aircraft and therefore should be strong enough for railroad use.
Technically, "Stainless Steel" is strictly a trade name applied to what are known as corrosion-resistant steels. It is a fabulous material that outperforms mild and alloy steels in so many different applications that no other material can match it. Stainless steel is similar to mild and alloy steels; it is an alloy of iron that contains at least 12% chromium. This high chromium content retards corrosion giving the steel its "stainless" quality. There are many alloys of stainless steel, which are broken down into two basic categories:
The chromium-nickel grades are the more common stainless steels used compared to the straight chromium types, due to the nickel content which provides excellent weldability and corrosion resistance. Also, this nickel improves some mechanical properties such as fatigue strength, toughness and ductility. People sometimes refer to stainless steels based on their chromium and nickel content: for instance, 18-8 stainless has 18% chromium and 8% nickel in it.
Stainless steel typically has a rather low carbon content, in the range of .08% to .15%, and sometimes as low as .03%. The carbon is needed for hardness, but it also can cause the stainless to become susceptible to corrosion at high temperatures. Some stainless steels are known as low carbon grades to minimize this carbide precipitation; others, such as 321, are special alloys that reduce carbide precipitation by combining and stabilizing the chromium at elevated temperatures.
A three-digit numerical classification system is used throughout the industry. We need to be familiar with only one of these three-digit series within the system - the 300 series. 304 is the most inexpensive and available stainless in the 300 series. It does not have the high temperature fatigue resistance that 321 does, but is considerably less costly and much more available. I would suspect that most available stainless steel track is from a 304 series.
Modulus of elasticity, coefficient of thermal expansion, and coefficient of thermal conductivity are too small to consider as a basis of comparison between stainless and nickel-silver, but coefficient of thermal expansion is a factor in using aluminum as it is around 30% greater (13.1 compared to 9.9) and if you live in an area with large temperature changes this must be considered.
Nickel-silver is in fact copper alloy C75700 made from copper, iron, lead, manganese, nickel, and zinc. The common 18% nickel content in most railroad track is resistant to atmospheric corrosion and acids. Outdoor samples develop a thin brownish green protective patina, however all nickel-silver alloy will tarnish in the presence of sulfur. Little can be said about it's properties unless a specific metallurgy is known, but assuming a standard 18% nickel content, it ranks very similar to brass in conductivity, workability and, surprisingly, corrosion resistance.
Knowing all this, my opinion is to use nickel-silver if you want the rails to weather eventually to a brownish green and still have the workability of brass, BUT since you live in an area subject to acid rain, corrosion will set in and tarnish the rails. Use stainless if you want a rail to be forever silver, but keep in mind that it is much harder to solder or bend. Now take into consideration what is readily available and stainless comes out on top with the most choices. If I had to choose I would use aluminum, but given your criteria I would have to logically pick stainless as the clear choice of material.
Just my
The Dixie D Short Line "Lux Lucet In Tenebris Nihil Igitur Mors Est Ad Nos 2001"
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