The first section from Crewe to Chester was built by the Chester and Crewe Railway and absorbed by the Grand Junction Railway shortly before opening in 1840. The remainder was built between 1844 and 1850 by the Chester and Holyhead Railway Company as the route of the Irish Mail services to Dublin. The line was later incorporated in the London and North Western Railway. Between Chester and Saltney Junction, the line was, from the start, used by trains of the Shrewsbury and Chester Railway later to be incorporated in the Great Western Railway. So important was the line in the 19th and early 20th centuries to passenger, mail and freight traffic between Britain and Ireland that the world's first experimental and operational water troughs were installed at Mochdre between Colwyn Bay and Llandudno Junction. Their purpose was to enable steam engines to collect water without stopping. Later, considerable stretches of line between Chester and Colwyn Bay were quadrupled to increase line capacity but these sections have now been reduced to two tracks.
Main calling points
The main towns served by the route are listed below:
Principal through passenger services are London Euston to Holyhead, Bangor, Chester and Wrexham General operated by Avanti West Coast and Crewe to Holyhead, Cardiff to Holyhead and Manchester to Llandudno currently operated by Transport for Wales Rail. A revised timetable has operated since December 2005 incorporating a new service to and from Cardiff Central every two hours. The line still provides the UK railway part of the through passenger service to Dublin using fast car ferries from Holyhead to Dublin Port.
Future
The Welsh Government would like the line to be electrified, especially if Crewe becomes a rail hub due to HS2 in 2026. Chancellor George Osborne said in July 2015 that there was a "really strong case" for electrification of the line. The Electrification Task Force said that the Chester to Crewe line was a Tier 2 priority for being electrified in the CP6 period. A £50 million signalling upgrade programme is currently being carried out between Shotton and Colwyn Bay, which will see modular colour lights supervised from the South Wales Rail Operating Centre in Cardiff replace the manual signal boxes and mixture of semaphore and older colour lights currently in use, in March 2018.
