Ah, the Triplex. You know, there were four of them built, three for the Erie, and one for the Virginian. All were flops, the Erie's being scrapped by the late 20's, and the Virginian's rebuilt into a 2-8-8-2 and it's tender engine built into a 2-8-2. You've probably never seen any pictures of them on a head end of a train as they were used in pusher service.
I'm looking at a photo of one now, and I've no idea what that cylindrical thing is on the cab in front of the engineers cab. The two cylindrical things on top of the first set of drivers look like air compressors.
As far as conversion to electricity, and I'm assuming you mean going from a kerosene to electric headlight, I believe the FCC mandated the change just prior to the First World War. Whether this only applied to road engines and pushers were exempt I don't know. I can't find a picture of a Triplex with an electric headlight here in the "archives."
Adding insult to injury, the Triplexes were too big for the Erie's own shops! The Lehigh Valley had to do Erie's Triplex maintainance!