I'm building a 1.12.2 modpack for our community and one of our players resquested Immersive Railroading. I checked it out and it looks really nice so I added it to our pack. The server and client starts fine, but when I tried to connect to the server, I could log in but after a few seconds, I would get kicked out with a message about a java exception. I pulled Immersive Railroading and TrackAPI back out of our pack and server and am again able to connect just fine with no issues. I will attach the log files from my client.
2018-06-08-2.log
debug-1.log

It looks like either a forge conflict or a mod conflict. Can you post the logs from your server?

Here is the server log as requested. Hopefully you will be able to find something useful in it.
2018-06-08-6.log

looks like a journey map problem?