• Trams practically accelerate/brake all the time: short distance between stations, even that interspersed with road crossings and curves, there can be a 'traffic jam' on the line too.
  
• Stopping time at stations is short.
  
• Unlike cars, rail vehicles (or at least the 'proper' railway vehicles I am more familiar with) often get near maximum continuous power at the maximum permitted speed, that is, braking/accelerating is not such a peak in power use as for cars.

I'm not aure I understand the point about building power supply across obstacles. Do you mean catenary systems, or also the Bordeaux system?

_{*Lunatic*, n.
One whose delusions are out of fashion.}