I need +5 explosives to diffuse the bomb. I'm looking all over the place for a cookbook so I can do this quest (hopefully the train stays put when I go back. I've already found the bomb and that seemed to keep the train from leaving)

I already found the starting one and the one in the prison and tipton and used them . So I'm looking for a loot one. I've tried going back and forth to merchants but no luck with the random tables. Any help would be greatly appreciated.