B0rk3d! crash: http://pastebin.com/Tv2ycJah
Yes, Optifine.
I do not think it is related to optifine (i have a crud pc, i need a lowered video accel for mc to work!)

Any time i place ANY steamengine, that happens, but the RCSteamengine Low is RCsteamenginehigh with the industrial one, etc....

so... INSTALL DEM powerconverters SAMRG472 VERSION!
and use dem EU > BC conversion,
but cant go to pipes (no connection to pipes)
But i havent tested w/ extrautils yet.
c4urself!

???????????

The crash log does not mention BC
Even though it does mention RailCraft the java.lang.IllegalAccessError leads me to believe that it is forge / coremod related. Try updating the forge version and see if that helps. If it doesn't, try with only RC and then add mod by mod until it stops working.

In any case, I don't see this as a BC issue

Yes, this is optifines fault. There is a reason we ask people to remove it. I've seen this crash often enough to know what causes it.

herp derp, without optifine = 0-1 fps :3
my pc is jusst too crud

Learn how to talk properly dude!

yes!
i update forge, ic2, optifine.
trying asap!

Yes, this is optifines fault

...@cccp2, why are you still trying to use Optifine? Just get a better computer as soon as possible.