Hi Al:
Yes I have connected Superstreets directly to Gargraves flex track and it’s not hard. The Gargraves pins fit right into the Superstreets outside rails. Obviously the center rails can not be connected due to the configuration of the Superstreets center rail so you need to leave a gap and use an extra feeder wire. And there is a height difference so depending on what you are using for roadbed you will probably need to shimmy up the Superstreets.
But I was not aware that Gargraves makes anything other than a 90-degree crossover?
BTW, I’ve also connected Superstreets directly to Super O track and to O27 tubular. K-Line/Lionel did make a Superstreets transition track to mate with tubular O but I’m not sure that Williams by Bachmann continued that item when they took over that product.
When do you head to Florida?
HTH,
Bill