I think the provisions of the bill are in fact consistent with what you're after, because if you read the definition of “alterations”, you'll read that it includes “a conversion, an extension, and a change in the use”. Conversion is specifically what you referred to I think in your example of taking a rail tunnel and making it a truck tunnel or a road tunnel. That conversion is an alteration that requires GIC approval under clause 6.
On June 8th, 2006. See this statement in context.