▁that ▁speed ▁of ▁construction ▁was ▁remark ably ▁short ▁and ▁led ▁to ▁" many ▁fail ures ▁in ▁m ason ry , ▁brid ges , ▁etc ." . ▁ ▁The ▁railway ▁proved ▁expensive ▁to ▁build , ▁the ▁final ▁cost ▁being ▁under ▁a ▁little ▁under ▁£ 6 0 , 0 0 0 ▁per ▁mile ▁in ▁total , ▁Murray ▁in ▁ 1 9 3 8 ▁comment ing ▁that ▁this ▁rate ▁per ▁mile ▁was ▁one ▁of ▁the ▁highest ▁ever . ▁ ▁Tri als ▁and ▁first ▁train ▁One ▁of ▁the ▁earliest ▁tests ▁was ▁with ▁a ▁horse ▁pulling ▁a ▁single ▁carriage ▁carrying ▁direct ors ▁and ▁friends ▁on ▁ 3 1 ▁July ▁ 1 8 3 4 ; ▁at ▁that ▁stage ▁with ▁only ▁a ▁single ▁line ▁laid ▁throughout . ▁ ▁The ▁D & K R ▁claimed ▁that ▁tri als ▁expected ▁in ▁September ▁were ▁delayed ▁due ▁to ▁the ▁ris ks ▁to ▁labour ers ▁still ▁working ▁on ▁the ▁line . ▁The ▁first ▁recorded ▁train ▁with ▁invited ▁passengers ▁on ▁ 4 ▁October ▁ 1 8 3 4 ▁was ▁ha u led ▁by ▁the ▁engine ▁V aux hall ▁and ▁ran ▁as ▁far ▁as ▁the ▁William st own ▁Mart ello ▁Tower ▁at ▁what ▁is ▁now ▁Black rock ▁Park ▁before ▁returning . ▁ ▁The ▁engine ▁Hi ber nia ▁on ▁ 9 ▁October ▁ 1 8 3 4 ▁ha u led ▁another ▁train ▁of ▁invited ▁passengers ▁composed ▁of ▁eight ▁carri ages ▁and ▁in ▁this ▁case ▁travers ed ▁the ▁whole ▁length ▁of ▁the ▁line ▁and ▁back . ▁ ▁Pl ans ▁were ▁made ▁to ▁introduce ▁a ▁service ▁on ▁ 2