Will you have active vehicle traffic using the grade crossing such as a Car System or RC solution or is it a passive road network where you only need the signals/arms to work and the train to drive reliably?

If you don't have moving car/truck traffic through it your options are a bit wider. One option is that you install a segment of wire at road surface height to run in the middle over/in-place-of the studs. If you can use aluminum wire it can sit slightly proud/above the paving solution and when you sand it to have a slight flat upper surface, would blend better with a grey concrete/asphalt look (than a copper wire).

Look up some youtube videos on people constructing tram solutions - one option is to plaster in track and then scribe in the inside rail area. For DC/DCC solutions thats easy, if you need the center conductor, its a bit more tricky. Of course if you can use cantenary to power the trains, then its a bit easier, but you have the cantenary related complications.

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