At the time of the Assassination, remote trucks were very rare. The former Crosley ABC network station in Atlanta, WLW-A's remote bus had been under contract to CBS(?) Sports for football coverage and happened to be nearby. NBC(?) found out about it and promptly leased it for NBC's use in their news coverage.
For a picture of this bus, see the fourth image on Chuck Pharis' web site where it looks like his webmaster got bit by the spelling checker on the bus name:
http://www.pharis-video.com/p1660.htm
This WWII era Flxible bus was originally built with a pre-NTSC standard video cameras and had been acquired by the station from War Surplus. It had been loving rebuilt by the station to NTSC standards. It was thought that this remote van and equipment had been used in the atomic test in Nevada by the military. During the coverage, the bus had to relocate several times and its 30+ year old differential decided to fail. In a panic, they had two big wreckers hoist the bus on to the back of the very big flat bed trailer, where it lived, chained to the trailer, for the rest of the news coverage.
They were panicking as the Ampex VTR in the truck had to be carefully leveled before use and it was no longer possible here as the bus was sitting high in the air on the lowboy's wheel wells, but the recordings apparently did work well enough to be used with the equipment in this position.
This happened about 3 years after I had left WLW-A, so I'm repeating the story as I heard it from others, back in the day. WLW-A TV is now WXIA TV 11.