As far as I can remember, Eldar Titans have fields that can ignore some of the incoming fire. Not like Void shields where they just soak it up.
For this reason, the best way i've ever found for taking down any super heavy monstrosity or titan, although admittedly I've only ever fought warhounds, is the same for SMs.
Chainfists to the foot. If you can manage to get some terminators up there without getting killed along the way, all the fields don't matter in hth and you can use your chain fists to make yourself a door in the foot and bring that sucker down. Be warned that the titan will probably end up squishing some of the Termies itself as well though.
For this reason, the best way i've ever found for taking down any super heavy monstrosity or titan, although admittedly I've only ever fought warhounds, is the same for SMs.
Chainfists to the foot. If you can manage to get some terminators up there without getting killed along the way, all the fields don't matter in hth and you can use your chain fists to make yourself a door in the foot and bring that sucker down. Be warned that the titan will probably end up squishing some of the Termies itself as well though.