I do.
Qmaster's Collection"
+0GRATECONVTEK, in quake_part3.wad. Can't remember where I found it ir maybe I made it myself.
Tips:
Conveyor animated texture is choppy but you might try:
"High FPS Texture Animations (Preach)"
An alternative is to use custents which has a conveyor of sorts using multiple trains linked but they have the problem of z-fighting eachother due to ltime discrepancies causing them to get out of sequence and overlap.
The best method is to use my qrobot.qc package with its func_robot_controller to sync multiple "robots"....BUT OH WAIT, I didn't ever release it, and I never did test the conveyor belt idea I had planned...I was waiting to finish that map I've been working on forever that uses them in a clever way.