A couple of comments -
Regarding the train speed, I have heard that the usual practice for train speed over a newly resurfaced section of track is reduced until so many tons have passed over it. Then an inspection to ensure no settlement or problem areas exist before the TSR is lifted. So - with all new fill and brand new bridge I would guess that they want a LOT of tonnage across it before they raise the speed up to design values.
Regarding the abutments, piers, etc - it was specified in the final environmental impact statement (FEIS) that all would be removed in order to return the banks and stream bed back to an undisturbed state. This may have been a requirement to swing the deal for the new bridge, who knows. But any remaining piers would attract people, i.e. "hey, bet you can't climb that!" and possible mishaps arising from failed attempts - especially so close to the top of the falls.
Regarding the train speed, I have heard that the usual practice for train speed over a newly resurfaced section of track is reduced until so many tons have passed over it. Then an inspection to ensure no settlement or problem areas exist before the TSR is lifted. So - with all new fill and brand new bridge I would guess that they want a LOT of tonnage across it before they raise the speed up to design values.
Regarding the abutments, piers, etc - it was specified in the final environmental impact statement (FEIS) that all would be removed in order to return the banks and stream bed back to an undisturbed state. This may have been a requirement to swing the deal for the new bridge, who knows. But any remaining piers would attract people, i.e. "hey, bet you can't climb that!" and possible mishaps arising from failed attempts - especially so close to the top of the falls.
Joe