The Atlas Trolley runs fine on D-21 'Streets roadways, but jumps the rails about 70 degrees into a D-16 roadway curve, as its trucks can't swivel quite enough to accommodate the 14 3/8 (center rail to center rail) diameter of the D-16 curves.
Here it is after a simple mod: you have to disassemble the entire thing although no wires have to be disassembled. The swivel angles of the trucks are limited to D-21 by two curved slots in the chassis - one above each truck, through which small screws from the truck project up inside the slot, moving inside the slot. I just removed the screws (in the photo after the video: the screws do not hold the trucks on or have any sgtructural role, they just limit the trucks movement). Reassembled (care is needed to put the bump-and-go switch back correctly), it runs as good as it ever did but now chugs through D-16 as if made for it. If curves were any tighter you would have to remove a little plastic on the sides to prevent interference between trucks and trolley body, but on D-16 that is no necessary - it just clears.
I prefer the Atlas trolley to all others based on looks and size - it just "fits" my 'Streets better. Stick out on curves is about 7/16 inch (see final photo below), which means parked cars and traffic in the other lane have to watch out, but it runs nicely.
