UPY SD40N 318Kansas City MO Kansas City

This loco is set up as a Slug Mother, attached to the unit behind it for yard service. The SD40N is a rebuilt SD40-2 with a ZTR Control Systems NEXSYS (hence the "N") control module installed for Mother-Slug locomotive operations.

And what is this system a way to do? Manage of locomotive remotely?
For SD40, he has an unusual construction above the cabin.

@white.dead - Well, it does have remote control, but the NEXSYS may do more than that, such as reducing wheel-slip under heavy loads, etc. The rooftop box may be just the UP version of a cab air-conditioner, which was added much later in the loco's life. This engine was built in 1978, with original reporting marks of UP 3465.