To be honest, the PM has got certain plans as far as Railways is concerned ( hi speed trains, infra upgrade and so on). It was highly unlikely in any case that he would have given this portfolio to allies
In any case I do recollect some interview where he did indirectly indicate as to how Rail ministry used to be run previously during UPA times when trains used to be needlessly introduced even if there was no demand in the route and infra was not in place.Also remember him speaking abt ministers being preferential in only looking after certain states & so on.So I guess his thought process is that the moment you give it to some allies etc, it...
more... would end up going back to the same era.