We're almost a week into the second phase of the massive Commonwealth Avenue bridge project that's rerouted cars, replaced part of the Green Line with buses, and closed lanes on the Mass. Pike.

One person not peeved about the inconvenience of all this construction is WBUR's Alex Ashlock (well-known around the station for his early morning sunrise photos from WBUR's roof deck). He's been documenting the cranes, trucks and massive machinery moving the new bridge into place. For Alex, his photo-taking is driven by both nostalgia and fascination:

This is a good time to be in the crane business. Boston is crawling with them this summer with all the construction. I started taking pictures of the huge cranes on the project over by Fenway Park, but the Commonwealth Avenue Bridge Project is taking this to a completely different level. Three cranes weighing 600 tons each — 600 tons each! — are deployed on Commonwealth Avenue. They've been lifting the old steel bridge beams out of the demolished deck and placing the new ones in. I just love the way these cranes defy gravity as they climb into the sky, especially early in the morning when I'm walking to WBUR. The appeal of this project for me also has to do with this kind of work in general. For me there's something nostalgic about 24/7 manual labor, the fact that it still sometimes happens. I used to do it at a factory where my dad worked. There were three eight-hour shifts, seven days a week. It's reassuring just to stop for a moment or two and watch it happening today.

Here are some of the best photos from Alex — along with a few from WBUR photographers Robin Lubbock and Jesse Costa. And for more about the project — how long it's going to last, and how to avoid it -- check out our roundup.

Buses, cyclists and pedestrians pass through Commonwealth Avenue at the BU Bridge early on the first morning of construction. (Jesse Costa/WBUR)

A crane lifts one of the old beams from Commonwealth Avenue Bridge, as part of the bridge replacement project, on June 30. (Robin Lubbock/WBUR)