any websites that feature lantern lenses. I am looking for a red 8" for a pyle National light.

Try Kopp Glass, they manufacture many types of signal lenses including railroad types.
R.R. lenses often show up on ebay, as well.

Gord McOuat
OERHA / HCRR

I've bought lenses from the supplier Trans-Lite, they have been very helpful.

http://www.trans-liteinc.com/exterior_lighting.html

Richard Wilkens