Yeah well things have changed since 2010. Batteries are much more affordable and in 2010 I was getting 60c a kw/h for my solar feed in.
Now I am only getting 7c a kilowatt hour and batteries are now extremely affordable and not expensive at all so again why am I putting solar out for 7c kw/h to pay 18-39c to bring that power back in. The prices make batteries extremely viable in 2020 and why would I ever stay on that peak/off peak rate when I use power in the middle of the day. The solar train company would save so much money storing that electricity in batteries instead of getting it from the grid in 2020.

The solar train is in motion around 2h a day on the current timetable, roughly 20min an hour.  So you are paying for a battery for just 2h a day.

Feed in Tariff around 8-12c/kW according to a few sites I googled for the area, off-peak Tariff is similar, maybe a 1-3c/kW more expensive. So for those 2h a day you are feeding in you are being paid roughly the same as you can buy back from the grid in off-peak late at night. So basically cost neutral or very close to it. Battery has no economic advantage and the train is still "carbon neutral".

Option 2, avoid the off-peak charge, bigger battery on train to accept more charge when plugged in. More solar panels on the train also.

Back to my tram option
As an example, Z1/2 class tram from Melbourne
- weight 19 t
- 4 x 57kW motors
- Feed in voltage is 600VDC,

A standard 60kW Tesla car battery is 375 V, so two of these batteries in series would be suitable supply for 120 kW which in theory would run the tram at full power for ~30min, a condition the tram would never operate in.  Just power to track speed then mostly coast the remaining distance with slight touch of the throttle occasionally.

install a short overhead section at each station for charging the battery. On arrival raise the pano for charging, on departure lower. Could be hard wired to the throttle control.

Assume track speed of 50km/h, then Mull'by achieved in about 20 min with stop at North Byron.

Stations are cheaper, as lower height. Very little modification to the tram. If you have some concerns on charge, throw in a small gen-set, that is back up power to enable return to home under its own power or mostly operate as a range extender for the battery.