a large worthington 6 sa feedwater heater was fitted with a 7 sa pump to handle the enormous boiler's thirst. the six-wheel leading and trailing trucks were added, as the locomotive was too heavy for four-wheel units. the streamlined art deco styled shrouding of the locomotive was designed by raymond loewy, a design concept based on his earlier streamlining design for prr k4s #3768 in 1936, for which he received u.s. patent no. 2,128,490. raymond loewy conducted the wind-tunnel test by using the clay model of s1 at guggenheim aeronautical laboratory for the design of its streamlined shrouding, and it was the same laboratory where he conducted testing of the streamlining of prr k4s #3768. the design of the smoke lifting plate around the smokestack on s1 was improved based on the wind-tunnel test result from guggenheim..