apart from 2 bankers there is one more lead loco so all will not fail at once?
Also if one passenger train is coming up from subramanya, say a goods train start from sklr. now if goods locos - all of them - fail, then still they can switch tracks at one of 5 between station and make the goods derail or hit that stop like thing at station loopline. so failed goods train wont be on mainline and hit passenger train.