After an accident with a through LNWR train to Tenby, Szlumper rebuilt the stations at Tenby and Pembroke, and extended the P&TR further into Pembroke Dock, to allow larger trains to access the line from 3 August 1870. The M&MR promoted the benefits of the P&TR to access Pembroke Dock to its customers in the Midlands, but the relationship only prospered for three years after the P&TR ceased working east of Whitland station over the Great Western metals, from 31 July 1872.