Find it interesting that PG&E specified (and PUC agreed) that this power configuration does not authorize high speed rail operation; that's going to take a different study.

There are occasions when power grids use short DC interties (basically, within a substation) to isolate areas that might not perfectly match in terms of AC operations. Wonder if Caltrain might need to do that once (if) HSR arrives on the scene. With HSR trains operating at higher speeds than Caltrain, and without as much regen along the way (fewer stops, more cruising speed running even though not actually high speed on Caltrain), they're going to generate higher power demand.

Also thought it interesting that one item they focused on was the harmonic noise generated in the line by on-train power electronics. More of that and stronger from HSR operations might trigger some more ambitious interconnect requirements too. But that's OK; it's clearly a case of "this is good enough for Caltrain; we'll deal with HSR if it ever happens" and HSR would be on the hook for any changes.