What is the estimated truck traffic for this rail-trucking hub?
2400 to 2800 trucks would enter the facility each day once the intermodal rail yard was fully operational. 
That's about 100 trucks per hour--
more than one truck per minute.
With Phase I of the warehousing complete, the number of trucks would be at 5000 to 6000 per day depending on which companies lease the warehousing space. 
At least three trucks per minute would converge on the rail yard and warehousing complex.

KDOT estimates 80% of the trucks would access the site by I-35 and 75% would leave driving north on I-35 (affecting roads in Johnson County and Kansas City).    
This video describes drayage truck issues and gives a good look at intermodal and port truck traffic.  The Gardner-Edgerton facility is intended to be and is referred to as an inland port.
How could 56-highway, the local access to the site, handle that many trucks each day?