FASTRACK-KIND OF WEIRD

Interesting, they're probably using old tin cans now.   Look inside the rail and see if it's a soup can?

In case you don't get the reference, remember the really old Japanese toys?  If you opened one of them up, the tin was recycled, you'd actually find printing from it's previous use.

Lionel released this Video in July 2018 recommending  soldering FT.

https://youtu.be/fuStJoh5Fv4

Interesting that there was no mention of using flux.

I read an article on soldering yesterday. The guy claims he can solder to any metal. He said there are many different solder types, flux and heat. You would just need to find the right combo. One issue with FT is that if you use too high of heat, you will melt the track bed. I use ring crimp connectors around the track tabs on the bottom of the track. Just bend them straight, place the ring and bend them back. Biggest issue with Fastrack (aside from the noise) is the pins. They can get loose and lose connection between sections. There’s a Lionel video on addressing this.

George

It may just be a different factory - the plating may have residual chemicals - it's all about using flux - more than the core solder has