This project is exactly parallel to what was done at Cal Ave a few years ago: in the original arrangement, to board a NB train you have to cross the SB tracks and stand on a narrow platform between the tracks. A tunnel is being built from the station (in the nominally west side) to a full-width northbound platform. This will improve safety and remove a constraint against southbound trains passing through when northbound trains are at the station. This will also allow ACE, which gave up on dealing with this complexity and has for several years just run it's trains past without stopping, to start serving this stop again.
Annoyingly, the tunnel does not appear to be going all the way under all the tracks, to the nominally east side (geographically northeast). Here's a Google maps view of the area:
View Larger Map There are a few workplaces over there. In the past I've seen people trespass across the tracks, but fencing seems to have been beefed up. The only legal way to get there is a via long detour to a road overpass several blocks away. Tunneling all the way through, and providing station access on the other side of the tracks, could also take several minutes off of the schedule of VTA's #10 SJC airport flyer bus:
All that crazy looping around on the south (nominally west) side of the tracks could be dropped, and the bus could stop more or less where that gray circle is.
Granted, extending the tunnel under the tracks would involve coordination of CalTrain, the UP, and future plans for BART and HSR, and anyone who expects that level of cooperation in US transit planning is clearly operating under the assumption that Proposition 19 has already passed.
I also noticed this odd stencil on a piece of rail:
Must be a story there.