▁first / last ▁not ches ▁is ▁when ▁the ▁motor ▁am meter ▁indicates ▁ 0 ▁A mp ères , ▁which ▁happens ▁when ▁passing ▁over ▁the ▁transition ▁position ▁with ▁the ▁lever ▁( the ▁driver ▁should ▁briefly ▁stop ▁in ▁the ▁middle ▁of ▁the ▁block ▁and ▁pay ▁attention ▁to ▁the ▁am meter ), ▁meaning ▁that ▁the ▁motor ▁contact ors ▁are ▁in ▁optimal ▁position ▁and ▁is ▁safe ▁to ▁proceed . ▁Fail ure ▁in ▁doing ▁this ▁may ▁result ▁in ▁flash es ▁that ▁will ▁damage ▁the ▁contact ors . ▁ ▁An ▁important ▁parameter ▁the ▁driver ▁has ▁to ▁consider , ▁especially ▁during ▁r he ost atic ▁ex clusion , ▁is ▁the ▁current ▁into ▁the ▁tra ction ▁circuit . ▁ ▁In ▁particular , ▁if ▁he ▁is ▁ex cluding ▁too ▁fast , ▁a ▁wheel ▁sli pp age ▁can ▁occur ▁( in ▁this ▁case ▁the ▁use ▁of ▁sand ers ▁and ▁reducing ▁thro tt le ▁can ▁help ), ▁and ▁one ▁or ▁more ▁maximum ▁current ▁rel ays ▁can ▁open ▁when ▁the ▁maximum ▁allowed ▁current ▁value ▁is ▁exceed ed . ▁ ▁The ▁locomot ive ▁is ▁protected ▁from ▁over ly ▁high ▁curr ents ▁through ▁different ▁kinds ▁of ▁rel ays : ▁ ▁General ▁maximum ▁current ▁relay ▁(" R M x "); ▁ ▁Three ▁motor ▁branch ▁() ▁maximum ▁current ▁rel ays ▁(" R M x ▁ 1 - 2 , ▁R M x ▁ 3 - 4 , ▁R M x ▁ 5 - 6 "); ▁ ▁RE C ▁( , ▁is ▁the ▁elect rical ▁system ▁used ▁to ▁provide ▁the ▁ 3 0 0 0 ▁V ▁coach es ' ▁elect