I don’t think it is too powerful. Has anyone come up with parameters for a siege yet? Perhaps:
1. Rail gun chooses between siege (SBR) exchange or the targeting of units.
2. Siege: one roll of a 6d for damage to IC facility. No counter to it by enemy - like V2 rocket fire.
3. (OR) First strike Salvo in attack: Roll 2 dice hit at 4 to have a maximum kill of two units that can’t fire back.
However, the enemy has to be able then to target it for destruction. It should be able to be subject to bombing. Thoughts on rules for this? Realistically, successful bombing of it would totally destroy it and it would be replaced by a new one which could be too expensive. Can it just be damaged and repaired like a base or airfield?