I do know that Milwaukee Road operations could indeed use regeneration to aid in powering another train on the system. But as I was told, by MILW people, it could indeed put power back into the grid.
Boxcab, I know that putting power back on the grid depends on how the rectifier system works, still now here in italy it is not possible as the DC power would have to be transformed in AC @ 50Hz, as long as I know it is either not feasible or too costly. If MILW had a DC power grid, (I knew in the old times, it was sometimes the case) for sure, otherwise they probably had their own system to convert DC back to AC. In any case I would have loved to see something like a 10MW US size electric.
They used MG (motor generator) sets to convert AC to DC for train power use. And as I understood them, from talking with substation operators, those same sets could covert the DC back to AC, during regeneration, and feed it back into the power grids. Resulting in the railroad not just paying back their used electricity, but the power companies actually owing the railroad some money.
Maybe I got it: in Italy we used Diodes made with vacuum tubes filled with mercury to have DC, these I think can not do the reverse, MG of course can. I got from an old book on early FS electrics that mercury diodes replaced MG for ease of maintenance. FS by the way owned both the power plants (mainly hydroelectrics) and the main feeder grid for railway use (they sold the lines a few years ago), as I connect all the pieces, probably the saving from maintenance bought out the surplus power. Earlier three phase AC were able to put back power to the grid.
