Oh forgot it was that time of year that they get typhoons. Needless to say, they got some serious dry cleaning to do for those trains.
They will be probably scrapped instead.
The mud was almost as high as the passenger windows, wich means that all the bogeys, electric mototrs, underfloor equipment (wich includes traction converters, compressors, auxiliaries, ATC recievers and on-board system, air conditioning and many many more) and even the interior (the mud probably filtered thru the doors) are unserviceable, soaked in not just water, but mud filled with organic rubbish and whatnot, and cleaning them is impossible.
Not only, there will be any sorth of thing inside evry duct, conduit and void in the car body as high as the mud reached.
Even if they manage to completely clean them (wich may take around 6-8 months per trainset, as they're 12-car trains and a total of 10 sets) they will have suffered unrepairable corrosion damage, wich will mean they will have a far shorter lifespan (around a quarter) than other trains of the same series.
The probable solution will be to postpone the retirement of E4 and E2 series trains as they temporarily replace the trains damaged by the flood until newly-built E7/W7 sets are put in service.