Blind guess for starting a conversation... probably 2-3x the cost of the Siemens ACS.
- Price for the Siemens ACS is a production cost, we're talking a one-off here
- Before you start putting it back together, there would be significant cost associated just getting a GG1 "ready" to start putting it together. I would estimate 1/3 of the total would be initial remediation.
- Ability, or the inability to produce some necessary components (castings) could blow the budget to the moon.
If someone is that serious, it would probably be better to start with a set of blue prints and produce a continuation/replica of a GG1. The GG1 was always just an electric. I do stand on my comment that adding a diesel genset would be totally impractical. Run it either off the catenary, or turn it into a slug.
Rusty they'd need to clear it with Lionel first, but pantograph LEDs making the little simulated sparkies would be unique. Raise the pantograph to feed it of an imaginary catenary.
