Certainly looks like there could be pockets in the bar for bearings. Fine if the rolling road is only for one particular model,,,,,as has been suggested, only a call away.
Certainly looks like the rail has slots milled into their width and very thin bearings put into the slot. Otherwise, could the bearings be running on the flange of the wheels, in which case you only need to lift the loco a few thou , enough to give you clearance from the rails. The front and rear bogies could be left on the rails.