Description of the Bug
I am using Buildcraft, and when I am placing any of the two fireboxes from RailCraft, the game crash immediately.
When I remove the Buildcraft mod, all is fine. I reported it to BuildCraft first and they asked that I also report it here.

To Reproduce

1. By placing a solid fuel firebox from RailCraft, the game crash immediately. Same happens when placing a fluid fueled firebox.

Expected behavior
It should not crash.

Logs & Environment
2019-01-31-1.log.gz
crash-2019-01-31_11.56.44-server.txt

MineCraft version: 1.12.2
BuildCraft version: 7.99.21
Forge version: 1.12.2-14.23.5.2806

Should be fixed in b5. wait for beta 5.

This submitted log is the first one for 31 January.

Will do, thank you.