There can be a substantial cost saving switching from diesel to electric fully.

India for example has been investing in this convertion last 2-3 years and are expecting 4-5 billion dollars savings every year by going full electric in the next 2 - 3 years.

The networks are very different , single public owner/lots of private owners , frieght/passenger ratios are different, Density is different etc,however there can be cost savings