mindset, though it makes sense. In IR the emphasis has always been to transport mazimum people in minimum cost, and that can only be done by longer (and by common sense heavier) trains. That calls for more TE and so more weight.
The only way lighter, speedier locos will make sense is when P-way is upgraded, S&T moves to next generation (just imagine, IR still takes blocks to 'upgrade' to RRI :p ) and our fav pet project i.e. HOG finally moves in right direction :)