TELEDOC thanks for the help. I do see the 1075E set in a 1937 catalog but it lists the set as not having a whistle, came with switches too. If we can trust the catalog listing. What also confuses me is the WC - which could mean Whistle Control? Which circa 1937 may have been a 48W shed or 1689W tender? Whistle control transformer is a #1030.
The box shipped from Lit Bros. store in Phila Dept 244 which I did find as the 'Toyland Dept' - am leaning towards the box as a store special..that 7000 number shows in no catalogs, Greenberg guides, or web searches from my end. Gotta get my hands on a copy Greenberg set guide one of these days.
Thanks again!