Long Island Railroad Oddity

In theory, not that hard. They already use radio control for G gauge garden railroading with battery power. The real problem might be having enough room for the batteries and the RC speed control gear,this would probably be about 6" long in O scale, so it might be something of a tight fit. Bachman just introduced a bluetooth based system in HO, and something like that in theory could be modified, given that it is small enough to fit into an HO engine shell , then it would just be a matter of fitting slim line LIPO batteries in the shell.If you didn't mind not being able to see into the car, you could use frosted window material, and have the entire interior space available.

Battery cars were tried by several roads.  They had the same problems electric (battery) automobiles did and still do....short range, long period charging, battery replacement.

That's pretty cool; reminds me of other trolleys with no poles. Here's a Mekarski compressed air trolley. The system was used in France for a while.