I've used many of these turnouts in the past, both powered and manual. The snap spring must be left in, otherwise, as you discovered, the turnout falls apart. (Peco turnouts experience similar difficulties if the spring is removed.) I had no problems as long as I left the spring in place. If you actuate it with a sprung linkage (like a "Z" bar), it will work perfectly. I never used the supplied throwbar, however; I always connected the linkage directly to the hole that the throwbar would ordinarily engage.