earlier times (even now), platforms are for people and luggages are loaded in end of platforms ie. ends (front and back) of train... think of situation if luggages, parcels are in the middle of platform and passengers at end of stations ??? earlier times, full Luggage Room coaches (even now found in goods train, long distance trains...) were made ... later, when luggages/ goods parcels are not so much (ie trains of short distances) and luggage rooms were nearly empty but passengers coaches are packed, half of the luggage room is given seater facility ie. SLR coaches are made ...