Today in WW II: 27 Jan 1943 The first batch of Ka-Bar knives [Knife, Fighting and Utility] shipped to the USMC from Union Cutlery Company of Olean, NY.  More 
27 Jan 1944 Russian troops retake Leningrad after 900 day siege.
27 Jan 1945 Soviet army enters Auschwitz concentration camp in Poland; more than 7000 remaining prisoners liberated.
27 Jan 1945 Memel, Lithuania liberated by Red Army.
Visit the Olive-Drab.com World War II Timeline for day-by-day events 1939-1945! See also WW2 Books.

R-4 Caterpillar Bulldozer / Tractor

Caterpillar introduced the R4 (6G series) in 1938, based on the earlier Caterpillar Thirty, and the R4 was produced until 1944. It was powered by a 4 cyl. gasoline engine and had both a 44 inch and a 60 inch track gauge (width). The R-4 had only one upper track roller, compared to two rollers on the Cat Thirty. The later D4 Caterpillar tractor was based on the R-4.

The rear winch was a Hyster D4 while the power control unit was by LaTourneau.

The dataplate states that the maximum drawbar pull is 7,332 lbs. and the maximum ground speed is 5.4 mph.

Thanks to Stephen A. Sarkany for help with this page.

USN Seebee R-4 Caterpillar Tractor with bulldozer blade, Carswell Strategic Air Command Base, Ft. Worth, TX.  Photographed 10 November 2006. Photo: Courtesy of Bob Pettit
USN Seebee R-4 Caterpillar Tractor with bulldozer blade, Carswell Strategic Air Command Base, Ft. Worth, TX. Photographed 10 November 2006. Photo: Courtesy of Bob Pettit.

USN Seebee R-4 Caterpillar Tractor with bulldozer blade, Carswell Strategic Air Command Base, Ft. Worth, TX.  Photographed 10 November 2006. Photo: Courtesy of Bob Pettit
USN Seebee R-4 Caterpillar Tractor with bulldozer blade, Carswell Strategic Air Command Base, Ft. Worth, TX. Photographed 10 November 2006. Photo: Courtesy of Bob Pettit.

USN Seebee R-4 Caterpillar Tractor with bulldozer blade, Carswell Strategic Air Command Base, Ft. Worth, TX.  Photographed 10 November 2006. Photo: Courtesy of Bob Pettit
USN Seebee R-4 Caterpillar Tractor with bulldozer blade, Carswell Strategic Air Command Base, Ft. Worth, TX. Photographed 10 November 2006. Photo: Courtesy of Bob Pettit.

Data plate of USN Seebee R-4 Caterpillar Tractor with bulldozer blade, Carswell Strategic Air Command Base, Ft. Worth, TX.  Photographed 10 November 2006. Photo: Courtesy of Bob Pettit
Data plate of USN Seebee R-4 Caterpillar Tractor with bulldozer blade, Carswell Strategic Air Command Base, Ft. Worth, TX. Photographed 10 November 2006. Photo: Courtesy of Bob Pettit.