The industrial tide turned against the growing town in 1880 with the cataclysmic explosion at Seaham Colliery, always a fiery pit where seven previous explosions had occurred. This one cost the lives of 164 miners and 181 pit ponies. Local bitterness caused by the pittance granted to widows, developed into a strike when the Maudlin seam was bricked up before bodies were recovered. Almost a year elapsed before coal production resumed.
Worse was to follow. The Chemical Works and Blast Furnaces closed down in 1885. The Rainton Pits, now worked out, were closed in 1896. The Docks were too small for many of the new large steamers to enter. Shipments declined. The Harbour was sneeringly referred to as the "Duck Pond".
For many workers the last straw was the sale of the Londonderry Railway to the N.E.R. Thought by many to be the best private railway in the country, it had often carried Royalty on their visits to the Londonderrys. In 1899 its last full trading year it had carried more than half a million passengers while the goods and mineral traffic was nearly one million tons.