by kato
george matthews wrote:One way of arranging that would be to start the tram while connected to a short overhead - that is, use the external supply to power the start up and rely on the internal power once the tram is moving.That's pretty much how the originally planned sections without catenary were designed - no stops in that section, the tram could just start from the last stop before, enter the catenary-free section and then "coast" through with only internal power.
Can't really do that with dozens of stops though, each with only a small section of catenary to "recharge" - each of those stops would then require its own power supply substation, which would be prohibitively costly (both in initial investment and in maintenance). In addition, if you want to maintain short intervals with multiple lines on one route in a network you will likely have trams waiting at intersections or before pulling into a stop until their track is clear - the network here for example has intersections that see trams passing up to every 40 seconds from various directions.
