Permanent Way Inspector
ModeratorAU Supporting Member
Gathering Team Member
- Aug 24, 2003
That is a very hefty assumption. Usually power drawn is regulated based on the design voltage of the territory in order to keep things from overheating in lower voltage territories due to the consequent higher current draw. That is why total available power for lower voltage catenary is less and operational characteristics are degraded to some extent. The question is to what extent such regulation is in effect for 12.5kV vs. 25kV. I don't know the answer to that.The only thing I would add is that the power in Watts drawn for each voltage should be the same, although the efficiency of the transformer at 25Hz vs. 60Hz may be different this affecting power draw slightly. However the lower voltage means almost twice the amps drawn through the pantograph which might be an issue along with the variable tension catenary not providing as uniform a contact surface. I am not an EE so take my comments with a large grain of salt.
Another thing that is visible in the catenary in 12.5kV segment is the additional Messenger Wire in the catenary which is needed to deliver the higher current efficiently, sometimes with a heavier contact wire which requires more support. They are usually absent in 25kV electrification except in extremely heavy duty freight lines.