Hi,

---- Minecraft Crash Report ----
// Why is it breaking :(

Time: 10/05/14 00:36
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=592, y=192, height=0, width=0, u0=0.5781348, u1=0.5781152, v0=0.37501952, v1=0.37498048}
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 7 (amd64) version 6.1
Java Version: 1.7.0_21, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 305902264 bytes (291 MB) / 507838464 bytes (484 MB) up to 954466304 bytes (910 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
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 v7.2.165.1065 Minecraft Forge 10.12.1.1065 Optifine OptiFine_1.7.2_HD_U_C2 4 mods loaded, 4 mods active
mcp{9.03} Minecraft Coder Pack Unloaded->Constructed->Pre-initialized
FML{7.2.165.1065} Forge Mod Loader Unloaded->Constructed->Pre-initialized
Forge{10.12.1.1065} Minecraft Forge Unloaded->Constructed->Pre-initialized
Railcraft{9.0.0.0} Railcraft Unloaded->Constructed->Pre-initialized
Launched Version: 1.7.2-Forge10.12.1.1065
LWJGL: 2.9.0
OpenGL: GeForce GT 640/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: []
Current Language: English (US)
Profiler Position: N/A (disabled)
Vec3 Pool Size: ERROR NullPointerException: null
Anisotropic Filtering: Off (1)

Fixed it yourself?
If yes, would like to know "How To" ;)

Thanks in advance.

@RioT-LiNaRo easy fix: remove optifine

@riot-linaro : no... close by mistake sorry.

@AEnterprise : -1:
optifine really, really cool...
choose between optifine and railcraft is hard !!!

but mcpatcher works with.