Well I'll tell you the obvious and semi-obvious similarities:
Obvious)
1) Both escorting some sort of Object that is nesscessary for the missions completion
2) Cramped spaces, with plenty of over-hangs and stairs
3) Large bulk of forces moving together while the support classes help from the higher ground
Semi-Obvious)
1) Heavy-body type class with Miniguns galore, with medics buffing contantly in the back
2) Marksmen (Or sniper if you will) will hang around in back, waiting for vantage spot
3) The Object that is beneficial for completing the mission can only move if units (or in Brinks case: The Engineer) are within a close radius.
This puts this mission at a consensus that it is indeed very similar to the Payload matches of TF2, not saying this a bad thing... just pointing it out.