The Thermal Coefficient of expansion is the tendency of matter to change in volume in response to a change in temperature. Believe it or not Brass is almost as stable compared to Nickel. Aluminum is by far the least stable. Natural wood is the real determining element as they tend to have a expansion factor of at least 2X of that of the metal. PVC is in the same ball park. So, it is not the rail that is the “guilty” component but the material used for the ties.
Quote:I've been using code 250 outdoors since 1996, and code 332 since 1980. In all that time, I've never been able to do anything with the code 332 that I cannot also do with the code 250. Both withstand being walked on--even by the under-10 crowd who are not known for grace, occasionally trod on by hoofed critters, tripped over, etc. Neither is any more resistant to the forces of nature (expansion, frost heave, etc.) You've got to do the same amount of work each spring making sure your track is level regardless of which rail you use. Never have I had a derailment on my code 250 that could have been avoided by using code 332. In all instances, the roadbed is compacted crusher fines. So to those who still view code 250 as not being sturdy enough, my advice would be simply to try it. I think you'll be surprised.
... Like many of us, I need track that can hold up to being stepped on, at least occasionally. I would love to have something that's at least a little closer to scale though, but I don't know how it could be done short of putting concrete roadbed under it.
Later,
K
well damn, I just put it together and toss it down on the dirt n run it.
Actually the only test I have done is the loop on my deck, after a number of years the LGB track has stood up to snow shovels, solid ice, 100 degree weather… the Aristo track, ehhh doesn’t do so well in ice. I had to buy LGB ties and trash the aristo ties for two 60 inch pieces i had on the deck.
I started out with Garich Light Transport Code 250 brass track, but I guess I was stepping on it too much and then there was my dog, so I upsized to LGB 332 and it seems to handle the abuse. I did end up using the code 250 for yard tracks in my storage/train room.
I like the look of the new bachmann track for you narrow minded people. You know who you are. 
Me? I love my 332 stainless black tie track. Never really have to clean it and it holds up for the beating my 2 and 4 legged family members dish out, plus the occassional falling squirrel and tree branch. The 400lb wheelbarrow full of ballast? Not so much.
Kevin, you are correct about the work to make sure the track is level after the winter. I worked all September to ballast the track, straighten out the missalignments and so on, only to have a strong rain front come thru and undo about everything I had done in the previous month. Can you relate? I have an open house each Halloween. But it sounds like code 250 would be a good track for the sidings while using code 332 for the mainline.
Ron
Ok…so does anyone know who is selling the new bachmann brass track and best price?
OK, my friend F.W. sent a close up of the joiner and the profile of the Bachmann track. (From the Nürnberg Toy Fair)
(http:///NA-Fora/BachmannBrassTrack.jpg)
Note the trapezoid cross section of the rail head, hmmmm looks like someone looked at rail specs! 
Apparently the 2mm Allen screws have a big enough head to grip them with a pair of pliers.
Price?
That 2mm head should be sufficient to provide some “bite” so the screw won’t fall of the Allen wrench into the ballast forever to be lost.
These days the best track is the track you already own.
Victor Smith said::)
These days the best track is the track you already own. ;)
Steve Featherkile said:Robbie at RLD Hobbies has it in stock. $5.13 a foot for 12 -36 inch sections. $5.74 a foot for 12-12 inch sections. Ralph
Price?
Alan Lott said:...reminds me that when I first started on this journey a fellow clubmember advised me to use the grease on my rail joints so I did. It's dandy if you want to collect grit in your railjoiners....
I have never had to apply some of the 'grease' type products
Noticed ana.kramar on ebay has it for about $5/ foot in 3’ sections + shipping
I’ll stick with the AMS Code 250 Brass for a little over $3.00/ft.