▁approach ▁was ▁taken ▁– ▁to ▁increase ▁the ▁length ▁of ▁the ▁line ▁to ▁spread ▁the ▁grade . ▁The ▁old ▁route ▁was ▁retained ▁to ▁the ▁head ▁of ▁the ▁D inas ▁In cl ine ▁where ▁the ▁new ▁line ▁sw ung ▁through ▁ 1 8 0 ▁degrees ▁in ▁a ▁horses ho e ▁b end , ▁thereby ▁changing ▁from ▁heading ▁n ortheast ▁to ▁south west . ▁It ▁then ▁sw ung ▁past ▁a ▁new ▁halt ▁at ▁T reg arth ▁ ▁before ▁swing ing ▁north wards ▁again ▁past ▁a ▁new ▁halt ▁at ▁Fel in ▁Hen , ▁where after ▁the ▁line ▁head ed ▁more ▁or ▁less ▁straight ▁for ▁Port ▁Pen rh yn , ▁meeting ▁the ▁original ▁alignment ▁below ▁the ▁foot ▁of ▁the ▁March og ion ▁In cl ine . ▁ ▁The ▁main ▁line ' s ▁primary ▁purpose ▁was ▁to ▁carry ▁finished ▁sl ates ▁and ▁Full ers ite ▁( pow der ed ▁sl ate ) ▁to ▁Port ▁Pen rh yn ▁where ▁they ▁were ▁loaded ▁onto ▁ships ▁or , ▁from ▁February ▁ 1 8 5 2 ▁when ▁the ▁Ch ester ▁and ▁Holy head ▁Railway ▁opened ▁its ▁Port ▁Pen rh yn ▁Branch , ▁onto ▁standard ▁gauge ▁trains . ▁The ▁ships ▁and ▁standard ▁gauge ▁trains ▁took ▁the ▁products ▁to ▁national ▁and ▁international ▁mark ets . ▁Second ary ▁traffic ▁consisted ▁of ▁sl ate ▁materials ▁which ▁were ▁finished ▁at ▁work sh ops ▁at ▁Port ▁Pen rh yn ▁into ▁bit umen ▁blocks ▁and , ▁not ably , ▁writing ▁sl ates ▁on ▁which ▁the ▁port ▁had ▁a ▁British ▁near - mon opol y ▁in ▁the ▁ 1 9 3