The photo below is from an article in ARMOR (September-October 1997), prepared at the U.S. Army Armor Center at Ft. Knox by Dr. Robert S. Cameron, the Armor
Branch historian. The photo is captioned "The M-26 tank, seen here on an M8 tank transporter, did not enter combat in the European Theater until the final days of WWII. Its armor protection, 90mm gun, and modern torsion bar suspension finally put U.S. tankers on a par with their German opponents."
Dr. Cameron provided Olive-Drab.com with an excerpt from "Report of Army Field Forces Advisory Panel on Armor, Vol. II, 1949, Annex E: Details of Report, Implementation of War Department Equipment Board Report (WDEBR)," which states on P. 29:
WDEBR, Section XXII, Paragraph 5 sets up a requirement for a transporter capable of carrying the heaviest ordnance equipment or equivalent weight in cargo and capable of operation from either end and movement in either direction with equal facility.
The same report states in Annex E, Section b, Implementation, Paragraph (1):
Heavy transporter T8E1 was developed to meet requirement (1). OCAFF [Office Chief of Army Field Forces] concluded that no tactical requirement exists for a vehicle of this particular type, its cross country ability is not desirable or necessary and its excessive weight, large size, and limited payload makes its battlefield value most questionable. (Ltr, AFF Board No. 2, 11 Aug 48, subject, "Cancellation of Test of Heavy Transporter T8E1" and 1st Ind, OCAFF, ATDEV-6. 451, 27 Aug 48).
The evidence is that the M8 of the photo caption is the T8E1, an experimental vehicle that was cancelled. Thanks to Dr. Robert S. Cameron, Armor Branch Historian, U.S. Army for help with this page. If you have additional information about this vehicle please contact Olive-Drab.com.