▁four ▁leading ▁whe els ▁on ▁two ▁ax les , ▁four ▁power ed ▁but ▁un cou ple d ▁driving ▁whe els ▁on ▁two ▁ax les , ▁and ▁no ▁trailing ▁whe els . ▁The ▁arrangement ▁became ▁known ▁as ▁double ▁single . ▁ ▁Us age ▁ ▁This ▁very ▁unusual ▁wheel ▁arrangement ▁was ▁used ▁by ▁D ug ald ▁Dr um mond ▁of ▁the ▁London ▁and ▁South ▁Western ▁Railway ▁between ▁ 1 8 9 7 ▁and ▁ 1 9 0 1 ▁on ▁two ▁classes ▁of ▁divided ▁drive ▁ ▁locomot ives , ▁the ▁T 7 ▁and ▁E 1 0 ▁classes . ▁The ▁absence ▁of ▁coupling ▁ro ds ▁enabled ▁the ▁driving ▁whe els ▁to ▁be ▁more ▁widely ▁spac ed ▁than ▁on ▁a ▁ 4 - 4 - 0 ▁locomot ive ▁and ▁permitted ▁the ▁inclusion ▁of ▁a ▁larger ▁fire box ▁ ▁Seven ▁locomot ives ▁of ▁the ▁type ▁were ▁built ▁which ▁performed ▁ade qu ately , ▁but ▁also ▁displayed ▁dis adv antages ▁over ▁a ▁ 4 - 4 - 0 ▁and ▁so ▁the ▁type ▁was ▁not ▁perpet u ated . ▁ ▁References ▁▁▁▁ 2 2 , 4 - 2 - 2 - 0 ▁Category : R ail way ▁locomot ives ▁introduced ▁in ▁ 1 8 9 7 <0x0A> </s> ▁The ▁Park ▁Fre ew ay ▁was ▁a ▁fre ew ay ▁planned ▁and ▁partially ▁constructed ▁in ▁Mil w au kee , ▁Wisconsin , ▁United ▁States . ▁The ▁fre ew ay ▁removal ▁policy ▁resulted ▁in ▁the ▁demol ition ▁of ▁the ▁Park ▁East ▁Fre ew ay , ▁the ▁only ▁section ▁to ▁have ▁been ▁completed . ▁