Re: “Existing line but are the/have the tracks been replaced in anticipation of the new service?”
It was being pulled. Top speed 80 mph. The accident happened around 6 AM, which is total darkness at this time of year.
As far as I know, the tracks are brand new. The previous line routed through downtown Tacoma, which caused lengthy delays for autos and trains.
Politically, this is just another Left Wing multi-billion dollar boondoggle.
The train boarded in downtown Seattle. This is a work day, as well as a heavy travel pre-Christmas week, but just 77 passengers on board.
King County (Seattle) is also building an internal light rail system. Last estimated cost, $10 billion, which goes higher every few months.
The result? When completed, the light rail system will reduce rush hour traffic by 5,000 cars!
We could have massively increased bus routes and reduced traffic by 10,000 cars for $1 billion!