Hi zar,
Well, the first things that is rather obvious is that Buell has 5 times the force as McCulloch.
The second is, since you say that Buell had to move further that McCulloch, (from this I assume that the fought the turn before and McCulloch lost, which would tell me that McCulloch's cohesion will be low and Buell's not so low (if you win a battle you lose much less cohesion)) and that they started out in adjacent regions, so with lower cohesion McCulloch will not move as quickly. When Buell caught up with McCulloch, McCulloch was still moving. I don't remember if the rules say anything about catching a moving force, but logic tells me that if it happens the question is then who can get there force into battle formation quickest.
This is where my third point comes up. McCulloch is all lone.
IF his force is organized into a division it will still have a 10% penalty for being under-commanded unless he is a ** Maj.Gen., if it is not a division it will be far more under-commanded. The battle-report icons show at any rate that his force is under-commanded (the one with the three men standing next to each other); yours is in red his in blue (not under-commanded).
Since the battle was is Desoto MS I will again make an assumption, that McCulloch was retreating from Memphis towards Granada, which would mean that they were trying to cross the Tallahatchie River, which is a major river, and that without pontooners (Marines, Sailors or some such special unit). I don't remember reading that getting caught from behind while crossing a river has in-game penalties, but if it doesn't it should.
At any rate, all these points spell for disaster and that is what came about.
Two tips
- Always keep your forces fully commanded
- If you are trying to escape and can use rail movement, USE IT
PS I've also noted that your force doesn't have a supply unit. If at all possible always have one supply unit per division even if they don't necessarily need the supply unit to keep them in supply. Having at least one supply element with supplies increases the power of your force by 5 or 10%, plus they can soak off hits vs your fighting troops in trade for supplies.