sentences:  Work was focused on finishing several miles of railway either side of the tunnel and, although easy to the north, to the south, heavy engineering of cuttings and embankments slowed the work.Track is known to have been laid through the tunnel at some point prior to December 1863, as a company report mentions an accident in that month on a ballast train en route to Pencader, beyond the tunnel.Official government inspection was carried out in January 1864 and the tunnel opened with the rest of the Llanpumsaint-Pencader section of the line on 1 April 1864.