Axis of Blood & Iron (2014)

From publisher blurb:

In Cold Blood.
When the apocalypse roared in, it took the mettle of a desperate coalition to hold it back. Forged in the war against the undead, hammered by the demand of their own survivors, and wrought on the backs of a thousand thousand slaves, this axis is the largest bastion of what could still be called civilization left in the wastes. And while the fuel may be tainted with blood, the trains still run on time.

Welcome to the Iron Works, the industrial megalopolis which now rings the Great Lake. Trains and highways can speed you from the music and mechanical mayhem of Motor City, to the windy, deadly hub of Rail City to the bustling breadbasket of Mill City and beyond. Try not to notice the Iron Slaves glowing with sullen discontent at every turn. In the mighty Ironworks, the zed are kept at bay, but the politics will kill quicker than a bullet.

Not all of the land the Lake touches belongs to the Ironworks, however. On the northern shore lies the land of the Reclaimers. This frozen land and her friendly people had their borders forced by the Merican mob, bringing the undead plague and ruin with them. Now, they wait and prepare for the day they can free their threatened land and captive people from the power of the Ironworks.