I'd be interested in seeing an up to date H&S▸ assessment....
Probably no worse than any other street running tramway.
The main problem when the boat train was running was cars parked inside the yellow lines. In places they were some distance from the running rail due to the overhang of the mark 1s on curves. So drivers thought they could park just over the line and got hit by the train! Also the length of the train. So similar problems would arise if it was a steam/diesel heritage operation.
A modern tram would have much less overhang and be shorter. The only problems with a modern tram would be that it is potentially faster and quieter than a steam train