At the end of the Company’s independent existence in 1923, the NBR possessed over 1000 locomotives of all classes, from 0‑4‑0 shunting tank engines to the pride of the fleet, the 4‑4‑2 Atlantic passenger locomotives, which operated the key express services throughout the network.
The Company’s first engines were built by outside contractors in 1846 for the opening of the line, a mixture of 0‑4‑2 and 0‑6‑0 tender engines for passenger and goods traffic respectively. In 1871, locomotive superintendent Thomas Wheatley was the first to introduce a leading bogie design on the NBR, with his 4‑4‑0 express engines, numbers 224 and 264.
The Atlantics, designed by W.P. Reid and first built in 1906, were the finest engines ever built for the NBR, being universally admired. The last steam locomotive to enter the service of the Company was number 518, an 0‑6‑0 goods engine, which was completed at the company’s Cowlairs works in October, 1921.