That gap shouldn't have caused any problems for a bike crossing it. The same way that crossing expansion joints or railroad tracks or any narrow gap wouldn't.

SO.

I suspect there's something not mentioned, maybe even unknown to the OP at the time. The likeliest possibility is that he dropped a wheel into the trolley tracks, then maybe caught toe corner.

Anyway, my real question is why would anyone ride between trolley tracks, leaving himself so little room to swing and turn across to turn out of them?

Sorry for "blaming the victim" but IMO the problem isn't the tracks or gap, but the rider's poor choice of position, compounded by inattentiveness.