The demolition and reconstruction of Fifth and Sixth Avenues for the train offers Portland a chance to install a few small works of public art, literally underfoot.
I've had occasion to walk a long stretch of SW Broadway for the last few days, and I noticed that several of the streetcorners have the names of the streets in black and white tile embedded in the sidewalk at the intersection. Here's one example. 
It's at the corner of Broadway and Salmon, outside one of Portland's most traditional (and Laquedem-like) haberdasheries. Five blocks to the north is another example, this time at Washington Street. These tile street labels appear to be the remnants of a consistent plan of placing the street names at the intersections, but unfortunately only a few of these bits of Old Portland remain in place today.
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The Washington Street title appears to be newer and is perhaps a restoration done in conjunction with the adjoining building.
My favorite, the source of which I figured out only last week, is the corner of Broadway and Stark outside the old headquarters of the United States National Bank of Oregon, where handsome brass letters identify the intersection. 
Why there? Only recently did I notice that letters of the same style are embedded in the entrance to the bank building, identifying that august financial institution of yesteryear. 
(The institution now called "U.S. Bank" is a North Carolina bank that bought a Minnesota bank that had bought U.S. Bank of Oregon.)
No doubt most of the sidewalk corners along the Transit/Train Mall will be cut out and rebuilt as construction proceeds. Here's an opportunity to add a little bit of public art, with the practical side benefit that when it rains and we're all marching with heads down, we can still see where we're going, or at least where we've gotten to.