It’s not that horrible. 15kV 16.7Hz is still high power. And also, as the railway power network is essentially a separate network for electricity, changing all of this to the 25kV 50Hz system would be a big challenge and expensive as hell. Lastly, it’s not that clear-cut. While, yes, the weight of onboard equipment could be reduced down to a third for Transformers, you still don’t want your locomotives to be too light. They need to have some weight for tractive effort. IMO: not that bad, but still complicated to change.
It’s not that horrible. 15kV 16.7Hz is still high power. And also, as the railway power network is essentially a separate network for electricity, changing all of this to the 25kV 50Hz system would be a big challenge and expensive as hell. Lastly, it’s not that clear-cut. While, yes, the weight of onboard equipment could be reduced down to a third for Transformers, you still don’t want your locomotives to be too light. They need to have some weight for tractive effort. IMO: not that bad, but still complicated to change.