This is a topic that has been discussed many, many time in the IET Railway Technical Network Executive Committee meetings, with lots of different views and opinions on what is needed and how it could work. Anyone got any thoughts on this?
Really if there is to be anything more than lip service to the environmental aspects, then there should be no longer be any 'if' in electrification, and overhead wires running an HV at 50Hz AC should be the preferred way of upgrading existing lines. Modern AC controls allow regeneration by inverter and transformers back into AC supplies, so the arguments that used to supported using DC traction currents on the rails at a variety of voltages that date from the era of the mercury arc rectifier should now be retired. This reduces the number and complexity of feeder sub stations, and the risk to life, and potential for flooding problems is far lower.
I'm not sure why it is so much more expensive in real terms to convert lines to electric than it was a few decades ago, I suspect creeping bureaucracy , the use of layers of subcontracting leading to a lack of economy of scale, rather than actual change to the technical issues of making holes in the ground and installing gantries and insulators, though if others know better I'd be very interested. to know why.
Really if there is to be anything more than lip service to the environmental aspects, then there should be no longer be any 'if' in electrification, and overhead wires running an HV at 50Hz AC should be the preferred way of upgrading existing lines. Modern AC controls allow regeneration by inverter and transformers back into AC supplies, so the arguments that used to supported using DC traction currents on the rails at a variety of voltages that date from the era of the mercury arc rectifier should now be retired. This reduces the number and complexity of feeder sub stations, and the risk to life, and potential for flooding problems is far lower.
I'm not sure why it is so much more expensive in real terms to convert lines to electric than it was a few decades ago, I suspect creeping bureaucracy , the use of layers of subcontracting leading to a lack of economy of scale, rather than actual change to the technical issues of making holes in the ground and installing gantries and insulators, though if others know better I'd be very interested. to know why.
