Details of locomotive workings can be found on the excellent Class 37 Locomotive Group page.
The ensemble awaits its path back to Wigan. The up trains often ran early but sometimes passed Bangor as late as 13:00 to be turned back short at Gaerwen and follow the 12:41 Holyhead to Crewe as far as Bangor where they are held until the 14:45 Voyager to London has cleared the section, getting away around 14:52. Late running of service trains disrupted this on occasions.
The same pair were in action the following day.
A different duo visited us on October 6th - 37 682 Hartlepool Pipe Mill and 37 712