Try A-Line. I went to the site, you'll find it under Locomotive Details.
www.ppw-aline.com
Have Fun.... Bob.
http://www.modelexpo-online.com/cgi-bin/sgsh0101.exe?Cmp005CACBA23FNM=14&Cmp005CACBA23UID=2007062915151295&SKW=chain
Have fun
Gen-u-wine HO chain seems to run $3-$4 a foot.
On good days at Wal-mart, in the teen jewelry section, you can find feet of it on sale for a buck or two, varying styles and lengths.
YMMV, but it's worth a look.