The GMC CCKW

Here is a photo/drawing of a CCKW with rear mounted gin poles. Does anyone know if this was something the US used during the War and what it was used for?

http://picasaweb.google.com/MacRacDan/C ... 6680736882

This photo came from the Wheels of Victory website: http://www.wheelsofvictory.com/index11.html

Thanks!
Daniel

That is a pipeline truck. Specially made for the purpose