In a transit vehicle, such as a bus or rail car, wherein each vehicle side wall comprises a framework of upright posts or mullions spaced apart for mounting the vehicle windows therebetween, and covered exteriorly below the windows with strakes of extruded aluminum, slots are provided at selected heights in the front and rear sides, respectively, of each two mullions between which a seat is to be mounted. One mounting tab extends from the wall end of the seat portion of each seat, and another fr...