WDM2's were produced till 1998. So, many of them are still very young by locomotive standards! WAM4's production stopped in the early 80's, so most of them are close to their design lifetime of 40 years. However, in some cases WAM4's are being scrapped to make space to add newer locos to the sheds even if they are in appreciable condition. Once the locos complete their codal life ( currently revised to 35 years from 40 years earlier), it is up to the shed's decision to keep the loco running.