Remember it was an American firm PB that TfNSW turned to for expert light rail advice. Their advice was of course "no grass track" obviously because they (a) did not know of such a thing, or (b) they didn't have the technical competence to provide the design parameters.

Here is a light rail corridor through a US university campus.

Here is a light rail corridor through a French university campus.

According to the German Federal Ministry of Transport and Digital Infrastructure:

To quote from the German Government/Industry Light Rail Systems handbook (ISBN: 978-3-87154-500-9 June 2014) summation of "Green Tracks" on pages 319 - 327:
/"The positive effects listed here clearly demonstrate that green tracks can make a significant contribution to having a liveable, civilised city - in fact they are some of the reasons that existing ballast and asphalt tracks are being greened. //*At the time of writing, estimates indicate that there are around 1 million m*//*^2 *//* of green track in Germany*//"

Here is a view from Paris

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