This is what my players did. It does not have to make that much difference, the Ob team can try the same tricks to delay Griento as they would have done to delay Liss and provide Liss with a lot of financial aid to let him build faster.
I used the undead lizardmen and placed them in a position to assault Griento, and my players went for a pre-emptive strike on them . Otherwise sabotage some bridges and stick immovable rods in trains all the same tricks work to delay the pc's building the rail road