Can't be 100%
Firstly
RMM reason can't be electrified due to salt water is a good conductor of electricity
Secondly nilgiri railways, Kalka Shimla railways, Kangra valley railways, Neral matheran railways and lastly Darjeeling railways are all world Heritage Site & can't be modernized
Hence...
more... in one word
98 % chances of electrification will be justified.