Ah we always knew that when Fallout 4 got released, that the modding community would have a field day with it. We've already seen a baby bomb mod, a John Cena mini nuke mod and most recently a Macho Man mod.
However the most creative, weird and creepy mod to come out is the Thomas the Tank Engine mod. Deathclaws, mini nukes, Vertibirds and more have been changed/converted into the image of Thomas the Tank Engine.
Modder trainwiz explained on NexusMods why the mod exists, "I'm sure you have just like me, sat near your fireplace at some point, sipped tea and ate a small animal and said to yourself 'Why has nobody put Thomas the Tank Engine in Fallout 4 yet. I mean, he clearly fits in every possible way!'"
If you cast your minds back to Skyrim, there was a similar mod there, which changed the dragons into Thomas the Tank Engine. Well look on the bright side, at least now you have more a reason for liking the Railroad.