▁small ▁compress or , ▁feed ▁by ▁the ▁ 2 4   V ▁provided ▁by ▁the ▁batter ies ▁is ▁used ▁when ▁first ▁activ ating ▁the ▁locomot ive , ▁when ▁main ▁t anks ▁are ▁empty , ▁to ▁produce ▁enough ▁air ▁to ▁raise ▁the ▁p ant ograph ▁for ▁the ▁first ▁time . ▁ ▁Origin ally ▁the ▁locomot ive ▁mounted ▁a ▁ 7 - position ▁L - type ▁West ing house ▁bra ke ▁controller ▁and ▁wheel - type ▁locomot ive ▁bra ke , ▁later ▁replaced ▁by ▁the ▁more ▁common ▁O er lik on ▁F V 4 ▁and ▁RA - M 2 ▁le vers ▁respectively . ▁ ▁B rak ing ▁systems ▁▁▁▁▁ ▁The ▁locomot ive ▁has ▁three ▁kinds ▁of ▁bra kes : ▁▁ ▁Hand ▁bra ke : ▁manually ▁activ ated ▁by ▁two ▁whe els ▁in ▁each ▁cab , ▁one ▁for ▁each ▁bog ie , ▁which ▁make ▁the ▁bra ke ▁sho es ▁cl amp ▁against ▁the ▁wheel ; ▁a ▁total ▁of ▁four ▁out ▁of ▁six ▁ax les ▁are ▁bra ked ▁this ▁way . ▁ ▁Lo comot ive ▁air ▁bra kes ▁( F reno ▁Dire tto ▁or ▁Mod er abile ): ▁takes ▁air ▁from ▁the ▁main ▁res er voir ▁t anks , ▁by pass ing ▁the ▁bra ke ▁pipe ▁and ▁directly ▁loading ▁the ▁bra ke ▁cyl ind ers ▁of ▁the ▁locomot ive , ▁thus ▁bra king ▁it . ▁It ▁is ▁slightly ▁faster ▁than ▁the ▁continuous ▁bra ke , ▁but ▁bra kes ▁the ▁locomot ive ▁only ; ▁it ▁is ▁not ▁advis able ▁to ▁be ▁used ▁to ▁bra ke ▁a ▁full ,