Today is the 146th anniversary of the Battle of Lookout Mountain, the first day of fighting during the Battle of Chattanooga.
Chattanooga an odd duck by Civil War standards. it feel less like the usual Napoleonic style set piece battle seen so often in that war and more like a 20th Century battle. For one thing it was very terrain-centric. It involved a series of engagements and much of the real decision-making seems to have devolved on rather lower-level commanders. Indeed, reading Grant's account of the fight, one definitely gets a sense that he didn't have a tight rein on what was happening.
It's not a real popular topic for wargames, but it's not ignored. The old SPI quad game, which I've played quite a bit on Hexwar, does a reasonable job of depicting the fight despite it's ancient design techniques. Like many SPI Blue & Gray quads, the design limits the number of pieces the Union player can move each turn -- a crude but effective way of depicting command control problems without a lot of rules.
Most historical accounts seem to paint a picture of an inevitable Union triumph, but it surely didn't seem that way to those present. I think Grant was confident, but then confidence was probably his defining trait. Despite the fact the federals had elements of three different armies on the field and outnumbered Bragg's troops, the Confederates did have a significant advantage in terrain.
Aggressive CSA play, combined with a little luck, can see the Federal command restrictions become a game-losing liability, so it's an interesting contest. The game isn't enough of a simulation to be confident it paints an accurate picture of the relative chances of the two sides, but I think it may come surprisingly close to the mark.