▁increased ▁plant ▁capacity ▁by ▁ 3 5 %, ▁and ▁was ▁producing ▁the ▁" larg est ▁steel ▁cast ings ▁in ▁the ▁world ". ▁▁ ▁The ▁Commonwealth ▁plant ▁also ▁grew ▁to ▁cover ▁. ▁ ▁The ▁company ' s ▁success ▁in ▁supp lying ▁large ▁cast ings ▁and ▁parts ▁to ▁the ▁rail ▁industry ▁necess itated ▁the ▁need ▁for ▁more ▁capacity . ▁ ▁Origin ally ▁covering ▁, ▁the ▁plant ▁grew ▁to ▁ ▁in ▁ 1 9 1 5 ▁to ▁about ▁, ▁with ▁almost ▁ ▁under ▁roof , ▁by ▁ 1 9 2 4 . ▁ ▁With ▁the ▁completion ▁of ▁the ▁new ▁General ▁Office ▁Building ▁on ▁the ▁site ▁of ▁its ▁plant ▁at ▁ 1 4 1 7 ▁State ▁Street ▁in ▁Gran ite ▁City , ▁Illinois , ▁the ▁company ' s ▁headquarters ▁was ▁re located ▁from ▁the ▁Pier ce ▁Building ▁in ▁St . ▁Louis , ▁Missouri ▁to ▁Gran ite ▁City ▁beginning ▁on ▁February ▁ 2 3 , ▁ 1 9 2 6 . ▁ ▁By ▁ 1 9 2 7 , ▁the ▁facility ▁expanded ▁to ▁ ▁with ▁the ▁plant ▁itself ▁covering ▁approximately ▁. ▁ ▁The ▁found ry ▁alone ▁was ▁over ▁a ▁third ▁of ▁a ▁mile ▁long , ▁. ▁ ▁In ▁ 1 9 2 6 , ▁the ▁company ▁produced ▁a ▁" one - pie ce ▁locomot ive ▁bed ▁with ▁cyl ind ers , ▁steam ▁ch ests , ▁and ▁s addle ▁cast ▁integral " ▁and ▁delivered ▁it ▁to ▁the ▁Terminal ▁Rail road ▁Association ▁of ▁St . ▁Louis ▁and , ▁during ▁this ▁same ▁period , ▁cast ▁steel ▁under frames ▁and ▁tr uck