He leased land formerly owned by his uncle on which the Poynder & Medlicott "Lime Works" factory stood and built a new foundry, named the Northfleet Ironworks.

[4] In 1848, the Dinorwic Quarry in North Wales ordered two 4 ft (1,219 mm) gauge steam locomotives from Horlock.

[6] Alfred Horlock testified at the 1849 Parliamentary commission inquiring into the application of iron for railway bridges and other structures.

[8] The company was declared bankrupt in July 1853[9] and the factory was auctioned to shipbuilders Bell, Wells & Co, who resold it in 1857.

[10] The steam locomotive Fire Queen, built in 1848, is on display at the Penrhyn Castle Railway Museum near Bangor in North Wales.