Bob: did your transit lines (if they ran light rail) try energy storage from regenerative braking?

IIRC Sac RT tried it at a couple of locations (bridges flying over mainline rail) where ultracapacitors were installed at the substation feeding the bridge. Theory was that they could soak up the power regenerated by the CAF cars descending from the bridge and present it to cars climbing the bridge. Not sure how well (or if) they worked; RT never published anything about it that I know of.

The CAF's usually use their dynamic brake grids, which from the overheated smell of things when used hard might be a tad too small for the job (intended for backup use rather than all the time?). The old Siemens cars, of course, do not do regen - dynamics only (with more sufficient or better-located grids causing less stink).