Destroying Rails and Number of Armies

[powloon1]

I'm just picking this game up again and I am playing the Union in the full campaign.

My first questions concern army formation:

Can every 3*** general create an Army or is there a limit to the number of Armies that can be created?
If there is a limit does this change over the length of the war?
Are there any downsides to creating a lot of Armies to avoid the NM/VP penalties of bypassing a general with more seniority ?

In the East I have been pushing my cavalry behind rebel lines in an attempt to destroy the rail line linking Manassas to the Shenandoah valley. I have been using single element cavalry stacks for this but they do not seem to destroy the rail lines when ordered. Do you need a minimum number of elements to achieve this? Again linked to this do you need to stay in the province for a full turn to destroy the rail line or can you set the order and move?

Thanks in advance!

[Gray Fox]

Yes, a limit exists that changes each year. It's 3 armies in 1861, 6 in '62 and I always beat the AI by then, so someone else may be able to tell you for 1863. No downside exists that I know of to creating all the armies that you can.

A force set to destroy a rail line gets a percentage chance to succeed. The chance is based on the power of the stack. If you make a Division under a General and put 4 cavalry in it, this usually is a force of over 100 power for 100% success. Use one of the regional decision cards to further hide the unit. I've had such a Division with a hide value of 5. You can then move to the region, set the unit to destroy the rails and move out the next turn. Good luck!

[clandini5]

The number of armies should be 9 by 1863.