Removing Optifine helps, but its still a Bug!

Description: Stitching texture atlas

java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.rangeCheck(Unknown Source)
at java.util.ArrayList.get(Unknown Source)
at net.minecraft.client.renderer.texture.TextureAtlasSprite.func_147965_a(TextureAtlasSprite.java:217)
at net.minecraft.client.renderer.texture.TextureMap.func_110571_b(TextureMap.java:358)
at net.minecraft.client.renderer.texture.TextureMap.func_110551_a(TextureMap.java:122)
at net.minecraft.client.renderer.texture.TextureManager.func_110579_a(TextureManager.java:94)
at net.minecraft.client.renderer.texture.TextureManager.func_110580_a(TextureManager.java:76)
at net.minecraft.client.renderer.texture.TextureManager.func_130088_a(TextureManager.java:63)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:523)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:815)
at net.minecraft.client.main.Main.main(SourceFile:103)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Stacktrace:
at java.util.ArrayList.rangeCheck(Unknown Source)
at java.util.ArrayList.get(Unknown Source)
at net.minecraft.client.renderer.texture.TextureAtlasSprite.func_147965_a(TextureAtlasSprite.java:217)

-- Texture being stitched together --
Details:
Atlas path: textures/blocks
Sprite: TextureAtlasSprite{name='railcraft:anchor.admin.0', frameCount=0, rotated=false, x=3120, y=2112, height=0, width=0, u0=0.7617212, u1=0.7617163, v0=0.51562744, v1=0.51562256}
Stacktrace:
at net.minecraft.client.renderer.texture.TextureMap.func_110571_b(TextureMap.java:358)
at net.minecraft.client.renderer.texture.TextureMap.func_110551_a(TextureMap.java:122)

-- Resource location being registered --
Details:
Resource location: minecraft:textures/atlas/blocks.png
Texture object class: net.minecraft.client.renderer.texture.TextureMap
Stacktrace:
at net.minecraft.client.renderer.texture.TextureManager.func_110579_a(TextureManager.java:94)
at net.minecraft.client.renderer.texture.TextureManager.func_110580_a(TextureManager.java:76)
at net.minecraft.client.renderer.texture.TextureManager.func_130088_a(TextureManager.java:63)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:523)

-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:815)
at net.minecraft.client.main.Main.main(SourceFile:103)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

-- System Details --
Details:
Minecraft Version: 1.7.2
Operating System: Windows 8.1 (amd64) version 6.3
Java Version: 1.7.0_60, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 142356600 bytes (135 MB) / 662700032 bytes (632 MB) up to 1881145344 bytes (1794 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -XX:MaxPermSize=256M
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP v9.03 FML v7.2.211.1120 Minecraft Forge 10.12.1.1120 Optifine OptiFine_1.7.2_HD_U_D1 5 mods loaded, 5 mods active
mcp{9.03} Minecraft Coder Pack Unloaded->Constructed->Pre-initialized
FML{7.2.211.1120} Forge Mod Loader Unloaded->Constructed->Pre-initialized
Forge{10.12.1.1120} Minecraft Forge Unloaded->Constructed->Pre-initialized
OpenEye{0.5} OpenEye Unloaded->Constructed->Pre-initialized
Railcraft{9.0.0.0} Railcraft Unloaded->Constructed->Pre-initialized
Launched Version: 1.7.2-Forge10.12.1.1120
LWJGL: 2.9.0
OpenGL: GeForce GTX 670/PCIe/SSE2 GL version 4.4.0, NVIDIA Corporation
Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Resource Packs: [Soartex_Fanver.zip]
Current Language: English (US)
Profiler Position: N/A (disabled)
Vec3 Pool Size: ERROR NullPointerException: null
Anisotropic Filtering: Off (1)

Yes, but not my bug!

Just wonder why Railcraft is the only Mod (out of 30) causing this error?
But well... i guess no more answere since closed.

@RioT-LiNaRo that is cause railcraft is one of the few mods that uses its own custom system for texture stuff, optifine can't handle that

IC2 also suffers the same fate.

I know the cause of it xD It's actually a case of two copies of the same mod being in the mods folder. Say... build 145 of GC3 and build 180 of GC3. It's cos it's already 'registered' the texture for the block or item, and it's trying to register it for a different version.