I'm not sure what's causing it but when I updated the Java RE to the 1.8.0 171 patch, the game would load the main menu but fail to load the world dumping this file into my minecraft folder:

hs_err_pid15260.log

Removing ImR does fix the issue. I've Tried rolling back the RE to 1.8.0 161 but I've had no success in getting it to work.

Forge Mod Loader version 14.23.3.2675 for Minecraft 1.12.2
Java is Java HotSpot(TM) 64-Bit Server VM, version 1.8.0_171

ImmersiveRailroading-1.0.1_1.12
ImmersiveEngineering-0.12-81
TrackAPI-1.1_1.12

It looks like you have an intel GPU and recently updated your graphics driver. Try rolling that back

I just looked the Device manager and found that i have 2 display adapters. The intel and a Nvidia. I then remembered that I forced the game to use the nvidia in the past to boost the FPS. When I updated Java it might have undid the settings I had applied to the RE. So I'm going to see if setting the RE to use the NVIDIA that fixes the issue before I roll back anything.

Okay I just switch which GPU is use for the RE and it works now! I'm going to make a note about this in my troubleshooting folder.
Thank you for your help!