What i mean here is most times train tank is in dearth of water, either unfilled or semi filled and under such circumstance, the auto flush system will exhaust tank water quite faster....already no or less water will lead water getting exhausted faster, leading to again the same issue of hygiene with await of next Junction, where water refill occurs!!
Apparently this means train has to stop more for the same purpose & frequent water refill points need to be sanctioned in train route!!
Further, washroom isnt used just for defecation of solid...
more... but liquid relieve happens quite often,,,,closing door will lead dual flush (close-in & close-out) & just for liquid sanitation, such water flush is simply water wastage!!