I want to know the answer to the following question:
What year could be marked as year when electric railways more efficient than diesel ones?
All the background I'm provided with is that "However diesels were mainly used on single track lines with a fair amount of traffic  so that the lower fuel consumption of electrics may be in part due to better operating conditions on electrified lines (such as double tracking) rather than inherent energy efficiency.". Is that enough to answer the question?
Answer: no