Are you referring to the six-axle SD-type unit that's there? If so, it should be the MJRX 1023. It's a so-called "SD20" that was rebuilt from a Southern SD24. It's had a number of owners - MJRX is Railway Service Contractors. The paint scheme is generic RailAmerica. Never operated on the SJVR, but apparently was used on the Missouri & Northern Arkansas before the sold it off.