[INDENT]Perhaps one of the moderators could move those posts in the above thread into the beginning of this thread to keep all things in their own thread

I had to think about this for a while and check some things, but in conclusion I don't think that the Militia Swarm is as effective as you claim it to be Jarkko. Let's consider a few facts.
Militia, when in their own state have a strength of about 19[SUP]1)[/SUP]; that is with 100% cohesion and full supplies. Once they start moving their cohesion will start to drop quickly, depending on the terrain through which they are marching and the weather. If they enter a non-home state their strength and cohesion will drop again by 10% so that if they are supplied and rested their strength will be about 15 at the most; this is regardless of whether the state they are now in is friendly or enemy.
To damage a rail line you basically role on a 100-sided die per stack attempting to do so and compare the the strength of the stack to the die role. If you role <= the stack strength you damage the rail line. So a single militia attacking a rail line in a friendly state has just under a 20% chance of damaging the line in that region, if he's still at full strength.
Considering that you have to march to the region you are attacking and militia are not the quickest of marchers because they tend to lose cohesion rather quickly they will not be able to attack very far behind the enemy lines. Then they will need at least one turn to try to damage the the rail lines, at which time they have used up half of their General Supply (GS).
If you manage to meet-up and stack your militia up to have a better chance at damaging the rail line you will not be linearly increasing your chances, because each additional unit in the stack will reduce the stack-strength by another 5%; each militia requires one Command Point (CP) and each lack of a CP reduces the strength of the stack by 5%
[INDENT]EG. one militia unit alone has 19SP (Strength Points) in its home state, two [I]not stacked together have a total of 38SP, but if they are stacked together they have 34SP and three have 48SP. This is under optimal condition which are not often to be found on the field.
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All this considered, militia are not going to be sortieing very far behind enemy lines to conduct their raids, they will lose cohesion quickly and be lucky if they manage to damage a rail line before they must return to a supply source. If they are attacked anywhere along their path they will either not be able to complete their mission or will take heavy losses, either from battle or lack of supply or both. Because they have lack of range there are only a hand full of locations behind enemy lines where they might find supplies. The depth of this range should about be doubled to prevent the rouge militias from trying to find an unguarded town deep in enemy territory. For this one doesn't need 100 militia units to defend against militia raids. Add a few cavalry to these garrisoned towns to run-down those pesky militia with e couple of militia in reserve to repair a lucky hit on a rail line and your defense in-depth vs marauding militias is set.
All this doesn't even consider the question of how you are going to get militia close enough to the front and into a position from which they can swarm out without being detected first.
I'm not saying that they are not something with which I would have to deal, but I think that over a division of militia might be put to better use by building a division with that manpower.
I'm more worried about True-Raiders™ who are harder to detect, quicker, have a longer range and are more proficient in damaging rail lines especially if they are lead by Quanrill, Mosby, Forest or another competent leader.
[SUP]1)[/SUP] These examples exclude units being lead my a general. Therefore the lose of strength for being under-commanded is already factored in.