Towers of Power

You can actually solo this achievement if you got both a Horde and an Alliance toon.

If you want to do the achievement on your Alliance char, wait til Alliance controls Tol Barad. If on your Horde char, wait til Horde controls it. If you don't care, even better.
I will explain it in case you want to get the achievement on Alliance, of course you can simply swap otherwise.

1) Alliance controls Tol Barad. So Alliance defends, Horde attacks.
2) Put your Horde char near the northern bridge at the entrance.
3) Remove your gear on your Alliance char and wait til the next match starts.
4) Alliance will get ported to the center. Mount up and get to the bridge to engage the Horde NPC guards there.
5) Alt + F4 while in combat.
6) Log in with your Horde char and kill your Alliance char who should still be in battle with the guard.
7) Your Horde char can now mount siege engines! Grab one of the northwestern ones and drive it to the northwestern tower to deploy it there.
8) Mount up and move as quickly as possible to the southern group of siege engines. Get in one and deploy it at the southern tower.
9) Repeat at the northeastern tower.
10) Alt + F4 and log in with your (dead) Alliance char.
11) Wait til he's resurrected, mount up and get to the northwestern tower, put your gear back on.
12) Kill the siege engine there.
13) Proceed to southern and northeastern tower.
14) If your damage is decent, you should be able to destroy all 3 siege engines before one of the towers gets destroyed.

If you are unable to see your other char in battle, remember that war mode on / off gets you to different instances of Tol Barad. This can be useful to find an instance that is controlled by the faction of your wish or simply to find another battle instead of waiting 60 minutes.

You have to deploy the siege engines at different towers because otherwise they could destroy the tower too fast. If you're not fast enough to circle through all three towers in time, you could try to just deploy and kill two first, and then repeat the procedure in the same match for a 3rd.

From the band Tower of Power, probably.

Can now just destroy the abandoned siege engines with high level character. Can easily out dps the rust heal buff on them. no alts needed.

You need to be faction defending tol barad to attack them