gunrunnerjohn posted:The MTH smoke unit should work in your Hudson, I've put them in a variety of Williams locomotives.
Looks like 1 3/8" tall, 1 1/2" long, 1" wide, and the top shot shows you were the stack is located. You'll need the brass funnel as well, that's what I use to solder my brass stack extension to.
That small size is great. Would you be so kind as to give the actual MTH part number