on ▁Street ▁E lev ated ▁at ▁Pit kin ▁and ▁Van ▁S ind eren ▁Aven ues ▁in ▁ 1 9 0 6 ▁was ▁designated ▁as ▁B RT ▁chain ing ▁line ▁P , ▁and ▁chain ing ▁zero ▁for ▁that ▁section ▁was ▁at ▁the ▁same ▁location . ▁ ▁The ▁portion ▁of ▁the ▁ 1 4 th ▁Street – Can ars ie ▁Line ▁built ▁or ▁re h abil itated ▁under ▁the ▁D ual ▁Cont ract s ▁and ▁opened ▁in ▁ 1 9 2 4 ▁and ▁ 1 9 2 8 ▁was ▁designated ▁B MT ▁Q ▁beginning ▁at ▁Six th ▁Avenue ▁and ▁ 1 4 th ▁Street ▁in ▁Manh attan ▁and ▁extending ▁to ▁the ▁beginning ▁of ▁B MT ▁P ▁chain ing ▁at ▁Pit kin ▁Avenue . ▁Ch aining ▁zero ▁for ▁the ▁B MT ▁Q ▁chain ing ▁line ▁was ▁also ▁at ▁Six th ▁Avenue . ▁ ▁When ▁the ▁line ▁was ▁extended ▁to ▁E ighth ▁Avenue ▁in ▁ 1 9 3 1 , ▁chain ing ▁zero ▁for ▁the ▁B MT ▁Q ▁chain ing ▁line ▁was ▁not ▁moved . ▁R ather ▁than ▁change ▁all ▁the ▁signal ▁design ations ▁and ▁chain ing ▁stations ▁on ▁the ▁line , ▁the ▁new ▁section ▁was ▁extended ▁west ▁from ▁the ▁same ▁zero ▁and ▁designated ▁chain ing ▁line ▁B MT ▁Q W . ▁ ▁When ▁the ▁installation ▁of ▁autom ated ▁train ▁operation ▁required ▁the ▁complete ▁replacement ▁of ▁the ▁signal ▁system , ▁the ▁M TA ▁decided ▁to ▁make ▁the ▁entire ▁line ▁B MT ▁Q ▁and ▁move ▁chain ing ▁zero ▁to ▁the ▁current ▁comp ass ▁western ▁end ▁of ▁the ▁line