Sadly in my area there are no junkyards, and the only scrapyard prohibits removal of goods. Sad too, i've seen some awesome stuff in there. (I asked about an old ambulance cap I wanted to make a playhouse out of, and they said no.)
My best resource so far has been a local garage door seller. The new doors always get installed with new springs and the old springs get piled up in the back. I've gotten some small springs from single house doors as well as a few giant industrial ones for warehouse doors (Those need to be cut before wrestling in the forge!)
All are simply heated and pulled into a nice round usable stock, and I get it for free, which is also nice! ;)
It's true you shouldn't walk the tracks for RR spikes, but if you see some guys working the tracks you can always ask. Most don't care since they're the ones who have to clean up when they're done.