I was able to beat this on my second day of trying combining common advice from most other solutions and threads, and a solid breakdown by Ultrafiend on http://www.xbox360achievements.org/forum/showthread.php?t=18...
They keys that worked for me:
1)High ranked items, especially for Alisa, keeping her alive.
Same as most recommend , health, attack, elemental, defense, and I used drop boosts. Farmed occasionally on the
Roger hidden level on hard
2)Moving to the more open side of the train near the gun - allows knock offs and better view.
3)Used Devil Jin and spammed his laser eyes from a distance, keying the fly and laser buttons to the 2 trigger buttons. This worked really well covering Alisa while she tanked, especially getting the charging gargoyles to run in a line at us from the other side of the train
4)Hit the crowd once with the laser when Jin appeared, backed up to a corner to get the angle and punted Jin off with the gun. VERY satisfying.
Managed this on hard with some luck while farming and getting the strategy down. Only works if you can stay ahead of the gargoyle rushes. Whenever they killed Alisa and crowded me, I didn't last long.
Nothing original here, but it worked for me and I didn't see the Laser Spam on this thread. Hope it helps!