I don't have a minecraft crash-report but a Java crash-report apparently, i don't know if it's caused by railcraft but railcraft is mentionned a the start and end of the seconde file :/

https://www.dropbox.com/s/sbx9xxcx258gd9v/hs_err_pid3436.log?dl=0

https://www.dropbox.com/s/wmp6kcd5u6op0w0/replay_pid3436.log?dl=0

PS maybe a java 8 issue i have this since i update java

See: #479 (comment)

Duplicated with #479, #487 and was fixed in 32281d8
Java 8 no longer crashes with newest forge. If crashes use https://github.com/LexManos/LegacyJavaFixer.
Gladly Railcraft 9.5 will be published soon, but CovertJaguar doesn't have enough time to write a blog for it...