This is a misconception that wdm 3a is not able to pull a 18 coacher on flat terrain at mps of 110.
It's possible that ko shed has done this in order to increase the working life of these two also twins and it's components fuel efficiency.
Soon many of such wdm3a would near their expiry date. Better to use them to full before that time. What ever it is shed people would be analysing this pair on basis of performance and fuel efficiency and would act accordingly..
Many...
more... times ets staff attaches them owing to non availability or maintenance issue of other locos also