This network, similar to Providence, is a light-metro system. Unlike Providence, however, Worcester has a bunch of rail right of ways that run down key corridors in the city. Of the light metro lines (W1&2), only the section of W1 west of Union Station uses a new right of way, of which only about half would need to be tunneled. W3, on the other hand, would run down Park Ave for 90% of its route, apart from small sections at either end of the line.
Now, onto the routings:
W1 is an east-west line, using the existing commuter rail / Amtrak right of way (with extra tracks) up to Union Station, tunneling under downtown until June St, past Worcester State University and up to the Worcester Airport (if this proposal and East-West Rail happened, it would most certaintly append Boston onto the end of its name…)
W2 is the north-south leg of the network, running from Main-South in the southwest corner of the city, past Polar Park, up to Quinsigamond Community College in Greendale. This line would use the existing Amtrak right of way until Worcester Station, then use an abandoned rail right of way the rest of the way up to Greendale.
Lastly, W3 mostly exists to fill in some service gaps where other lines don’t serve, supplementing the rest of the system and expanding its reach. Most likely, this line would be a mix between center running dedicated lanes and street-running (no dedicated lanes).