The Great Rail Wars - Cry Havoc! (1998)

From Chapter One: Open Volleys Introduction:

In Cry Havoc! we're going to bring you up to date with all the rules changes since The Great Rail Wars began. Nobody wants to search through three or four books in the middle of a heated battle, so we've conveniently combined them in this chapter, letting you concentrate less on flipping pages and more on shooting holes through your opponent.
There are a few changes and expansions to the existing rules here, but that's not all. We've even collected all the new abilities and weapons from the GRW expansions to date. There are also the complete rules on duels and how to handle experienced and veteran troops.

From Chapter Two: The Lay o' the Land Introduction:

We just talked about how you fight your battles, and now we're going to talk about where you fight them. Here, we clarify a couple of areas from the GRW rulebook, but we also give you some new regions and strange locales for your battles.
There's also a section detailing the Strange Locales rail warriors may encounter. We've beefed these up and given the heroes more reason to explore these outposts of the Weird West.

From Chapter Three: More Magic, More Mayhem Introduction:

In the Great Rail Wars rulebook, we gave you about a dozen spells to arm your spellslingers. Since then, we've come out with a stampede of Deadlands: the Weird West sourcebooks filled with new arcane incantations and miracles to make the average cowpoke's ride even rougher.
This chapter contains the GRW conversions of many of those new spells. We've also tacked on complete spell lists for all the types of spellslingers in the game.

From Chapter Four: Fleshin' Out the Dead Introduction:

In the original Great Rail Wars rulebook, we gave you just the bare bones on using the Harrowed in your games. In this chapter, we show you how to make a Harrowed hero, plus we've got special Hindrances just for them, and a lot of powers only available only for these Boot Hill rejects. We've also included guidelines for converting your Harrowed character from the Deadlands: the Weird West roleplaying game.

From Chapter Five: The Miracles o' Weird Science Introduction:

There's a whole passel of strange devices that have found their way onto the battlefields. Guns that shock the opponent into next week, contraptions that let a man move underwater, and even steam-powered chainsaws! And there's the latest development in the area of science: alchemy and its potent chemical effects.