How can I complete the Factory Fort defense level?

I'm stuck at this level which requires you to defend yourself against a non-stop stream of enemy ironclads for a set number of turns. I've considered a few tactics, including using pioneers to set up blockades, using AoE weapons like the light cannon and the saber to destroy the tightly packed enemies, and to use cheaper infantry and fire-at-will tactic cards to form a blockade.

So far none of these seem to have worked, mainly because of how fast the enemies roll in. The blockades only have 5 health, and doesn't actually damage the enemy, so it only stalls the inevitable. The light cannon is powerful enough to destroy enemies in one shot, but takes a long time to set up during which the enemy would have already marched into the canon's dead zone. In the end the problem is that it's really hard to set up an effective defense with very little AP. What other decks are available that can complete this level?