With trains scheduled to roll along 12 new miles of light rail track in Portland by 2027, planning on the TriMet expansion continues to move forward, both on the proposed route and 13 stations between Portland State University in Southwest Portland and Bridgeport Village in Washington County.

The 2022 date to start construction on the $2.7 billion project will come quickly for one of the largest transit projects ever tackled in the city, an effort to create a 30-minute ride south from the downtown university while easing congestion on the much-traveled Interstate 5. 

But with a route that crosses I-5 twice, requires new bridges over roads and water and demands space to operate in an already congested area, planning the exactness of the route proves a challenging aspect. TriMet, the agency tasked with transit needs in the Portland metro area, laid out an update in June of the work on the plans for the extension. The agency knows where it will locate the 13 new stations but hasn’t finalized the designs of them. Along the way, planners want to remake Barbur Boulevard, the main lane of travel for the planned tracks in Portland, including widening the road and including five miles of physically protected bike lanes. 

Parking also provides a challenge, which has TriMet taking input from the public on how to handle park-and-ride plans or parking garages at specific stations. 

And all along the way, city planners from Portland to Tigard see the expansion as an opportunity to plan into the future, whether with affordable housing, urban renewal or even the smartest way to handle displaced homes and businesses. 

With plenty of questions still to answer in terms of finalizing route design, the budget also has its set of question marks. The $2.7 billion price tag for the project does leave out some of the ancillary infrastructure projects that will come with the reworking of roadways, such as replacements of some bridges and on- and off-ramps. So far, three local entities — TriMet, Washington County and the city of Portland — will each pay $75 million toward the cost. The state may kick in an additional $150 million. Voters will likely be asked to pay $850 million, still not enough to cover the entire cost of the project. 

As with any project the size of the TriMet expansion, plenty of preliminary work remains. But as we near closer to the 2022 construction start date, officials hope to have more answers than questions. 

Follow Tim Newcomb on Twitter at @tdnewcomb