Tacoma Dome Line

Sound Transit identifies preferred alternatives for Tacoma Dome Line: ProgressiveRailroading.com

Sound Transit's board earlier this week identified four preferred and other alternatives to study as part of a draft environmental impact statement (EIS) of the Tacoma Dome Link Extension project, which will extend light-rail nearly 10 miles between Federal Way and Tacoma, Washington.
...
The project calls for construction of four elevated light-rail stations in south Federal Way, Fife, east Tacoma and the Tacoma Dome.

The preferred alternative for the Tacoma Dome Station is near East 25th Street and west of G Street, which would be connected to the East Tacoma Station by a guideway.

The East Tacoma station would be built in near East 26th Street or East 27th Street, near Portland Avenue and north of Interstate 5. Fife Station would be located north of 15th Street, while the South Federal Way Station would be built along Enchanted Parkway near South 352nd Street near I-5, according to the published board motions.
...

New Tacoma Link light rail stations open to riders Saturday]

TACOMA, Wash. — The expanded Sound Transit Line in Tacoma will open to riders on Saturday.

The line will now connect the Tacoma Dome to the Hilltop neighborhood. The service area of the Tacoma Link will be doubled, going from five stations to 11 and increasing from around 2 miles to around 4 miles in length.

The expansion will also increase the number of Sound Transit Tacoma trains from three to eight.
...

To clarify, these are two separate lines/routes/projects. The "Tacoma Dome Link" is a light rail/interurban style service operating with a near-complete grade separation (largely elevated), using Siemens S70 type equipment and running several miles between stops.

The Tacoma Link, although called a "Link light rail" line, is actually more akin to a streetcar line, running Skoda and Brookville style equipment within street medians with stops every few blocks apart and at 25-30 MPH top speeds.

While Sound Transit considers them part of the same system, functionally and mechanically the only thing they have in common is the track gauge (and that they are both rail-based transit). Even if they do connect in Tacoma, it will not be a physical connection - passengers will get off one train and board the other. Just like Link to Sounder. Link to Bus. Tacoma Link to everywhereelse Link.