Memories from this ancient mariner:

There was also 3 phase operation thru the original tunnel (both ends accessible)
Used one phase on the rails, two phases on trolley wires, and a pole jumping "fireman" at the passing sidings on each end. Look for right-of-way on North hillside as viewed from US 2.Now a hiking trail; obtain map from USFS Skykomish. There are two abandoned tunnels; one on the sidehill and one on the loop above Scenic - may be vary difficult to find.

The East terminal of electrification was at Appleyard, East of the Wenatchee station. Now highway truck / container transfer yard. Motor shop foundation may be found.

I believe that I remember reading that Appleyard to Skykomish was converted to single phase AC thru the upper tunnel in anticipation of the completion of the present tunnel.

There was a secondary enginehouse at Skykomish, just East of the grade crossing. Concrete may be found.

There is a tunnel East of Berne, built shortly after WWII. Find the original right-of-way. You may find the remains of the watchman's cabin. Nasty series of curves.

One weekend, about 1947, I rode the (not very) Fast Mail #28, King Street to Wenatchee. (Back platform of the coach thru the tunnel) Walked to Appleyard and back, then returned to King Street via the day local, #5.

Enjoy reading and prowling.