Many moons ago I worked for the company whose logo is on the rear door: Transport International Pool (abbreviated “TIP”). TIP was a subsidiary of Gelco Corporation. According to Wikipedia in 2015, it is now called "GE Trailer Fleet Services". The dirty rear door and peeling logo lead me to believe that another company bought the used trailer from TIP.
I took this picture while eastbound on I-80 near Grantsville, Utah.