>>1134483Trolleybuses are most likely not coming back. My perception is that no city will be interested in a new setup, because of high cost and hurr muh ugly wires. Even existing systems are already working on extending their lines with battery operation. In those cases the wires are useful because they allow continuous charging over long stretches, but apparently it's not enough to justify new installations or even extending existing wire.
Call me backwards, but I don't much care for this trolley-battery hybrid thingy. Reminds me of the whole BRT business, cheaping out in the beginning, and having more problems in the long run, in this case with battery replacements. Modern trolleybuses used to have rather small batteries only for small detours (say 1-2 km autonomy), sometimes they even had an auxiliary combustion engine. Since like 99% or more of the time they ran under wires, the batteries lasted at least as long as any other regular bus battery, and also they were smaller, so replacing them is neither so bad for the environment nor too expensive.
However, with these hybrids which will regularily run on battery power you'll get the same problem as with regular battery buses, that eventually you'll find yourself constantly having to replace batteries, which is expensive and polluting, all the while you still have to maintain wires.
I'd be in favor of fully trolleyfying trunk bus lines and using standard trolleybuses with "small" batteries, and using regular battery buses for secondary lines, maybe hybrid units for secondary bus lines that happen to run for part of their line under wires.
I remember that in Schaffhausen where there's only one rather short trolleybus line they calculated that all together it was just about 10% more expensive to maintain in the long run over combustion buses. This would be even less for a larger system, since this is a tiny system that's the most difference that you'll get.