This video from oorail.com demonstrates how to create the in-motion tracking camera shot on a OO Gauge Model Railway. This shot is one oorail.com started using in 2013 in YouTube videos, its a pretty neat shot and relatively easy to setup. Two analogue DC controllers were used, one controlling the target of the shot, and one controlling the locomotive hauling the rig. No special modifications were needed, the shot was creating using off the shelf ready to run locomotives and rolling stock.