As a railfan, I want to see the Dinky remain rail but I think from a business perspective, NJT is thinking more on the bus end of things. If they do go with bus, they should match the times that it takes to travel by bus as much as possible with what it takes to travel by train from the current Princeton Station. The catenary system on the Princeton Branch dates back to when the PRR started running trains and it is certainly very costly to maintain. With NJT moving the Princeton Station to where it presently is right now has affected ridership a lot and a lot of that lost ridership may never return to the Dinky.
If running electricity is costly to maintain, they why can't the NJT de-electrify the Princeton shuttle and have DMU service on the branch? They've tested it before when the Colorado Railcar DMU tested on the Princeton Branch with a Comet V cab car back in 2002. Not to mention, the shuttle in general is a direct connection for residents of Princeton and students of the university to transfer on the same platform to Amtrak and NJT service. Using an environmentally friendly DMU would also have fewer emissions than a bus.
Here is another example of a branch line which is nearly one third the length of the Princeton shuttle, and uses DMU service equal with the need of ridership.
https://en.wikipedia.org/wiki/Stourbrid ... ranch_line