DM30AC Question

At what point along the line does an inbound train from huntigton, switch over from diesel to third-rail power? (The DM30AC)

I rode train 615 two or three times last May; I boarded at Hicksville and the lead unit, at least, was silent at that point. But DRN said they no longer do that.

For PJ trains, its Mineola going west, Oyster Bay trains do the switch over west of Mineola, and Speonk trains will do the switch at Valley, or Port headed west. All eastbound trains do the switch right out of the East River Portal.