White lines appearing on map.

[blacksheep81]

I've been having an error where in certain places of gmod maps, I can see white lines everywhere. They look as if a texture or a model has been screwed up. Pictures from d1_trainstation_01

Edit: My mistake, that's d1_trainstation_02, but these occur on numerous maps (stated below):

[IMG]http://img828.imageshack.us/img828/2348/d1trainstation020000.jpg[/IMG]

[IMG]http://img535.imageshack.us/img535/4511/d1trainstation020001i.jpg[/IMG]

I can't find much that affects them, but here are a few facts just in case:
-They usually appear on detailed maps, like city_08 maps, hl2 maps, most rp maps.
-The lines aren't always there, sometimes looking at a slightly different angle causes them to flicker, or disappear.
-They resemble power lines, and do usually occur on maps where power lines are part of the scenery. However, my cable (black rope) texture using the rope tool works just fine to the best of my knowledge.
-Sometimes when an NPC's or ragdoll's head moves, the lines can be seen in the background moving the same way, in correlation. Alyx, for example.

The only recent major changes are:
-One, that I placed hl2 beta props into gmod which replaced a couple of things such as possibly my fire texture (with nothing), barney, the combine, some props.
-And Two, I bought episode 2, although I realized this error before that, and ep2 changed nothing.

Any help would be greatly appreciated, if I figure a way to fix it/make progree I'll post here. If there is anything else you need to know, I'm all ears/eyes. Thank you all.