Gyro power plant for example: http://en.wikipedia.org/wiki/Gyrobus
Compressed air: http://en.wikipedia.org/wiki/Pneumatic_motor
True. But the thing is that: it sucked
You know that "lever up, tram goes, lever down it stops"? It was something like this: https://en.wikipedia.org/wiki/Potentiometer#Rheostat
Sure, mass transit is good, electrical/hybrid ones even better, but as much as I hate mechanical ICEs, the electrical ones weren't much better.
And mass transit can profit a lot from hybrid technologies
> While it's true that National City continued ripping up lines and replacing them with buses — and that, long-term, GM benefited from the decline of mass transit — it's very hard to argue that National City killed the streetcar on its own. Streetcar systems went bankrupt and were dismantled in virtually every metro area in the United States, and National City was only involved in about 10 percent of cases.
The impact they had is probably arguable.
Still, I think that no city in the United States came up with an idea how to benefit from trams, the way European cities did, is a little bit strange.
After all that's the country that hosts biggest ball of twine in the world.
http://en.wikipedia.org/wiki/General_Motors_streetcar_conspi...
You probably can't say that what they did was decisive as there were more factors in play but they tried in a covert way and prevented any chance of recovery.
For a dense city having a streetcar is no-brainer. Whatever you pay for planning, building and maintaining light-rail and subsidizing its operation, it will pay for itself in increase in taxes collected from business growing thanks to offloading road network from whole lot of cars, lower traffic, cleaner air and lower necessary car ownership.
All this clean electric car revolution with energy recovery, low number of moving parts and so on, that's happening now, for trams happened 50 or more years ago.