CREATE TABLE table_78251 ("Year" FLOAT, "Manufacturer" TEXT, "Model" TEXT, "Length  ( ft. ) " TEXT, "Fuel or Propulsion" TEXT, "Fleet series" TEXT, "Quantity" FLOAT)

Name the fleet series with a quantity of 5
SELECT "Fleet series" FROM table_78251 WHERE "Quantity" = '5'
SELECT "Fleet series" FROM "table_78251" WHERE "Quantity" = '5'