Lehigh Valley used to run solid blocks of empty gons at the head of
trains.
There's a photo of one of these trains in the Summer '04 issue
of "Locomotive Quarterly".
There a couple of photos showing trains headed by F3s with blocks of
MT gons up front in the April issue of F,D,&S ("Flags, Diamonds and
Statues" - magazine of the Anthracite Society).

Said magazine arrived in my mail box this week.

Ed