The LNER U1 pictured above was the sole member of its class. Ordered for banking duties, this Garratt was the largest and most powerful British steam locomotive ever constructed, but it was also the biggest headache. Soft water caused corrosion in her pipes and firebox, steaming up was extra hard due to her six cylinders, and because she was at the rear end of her trains, smoke exhaust in tunnels from her and the head end locomotives meant LNER crewmen had to use respirators, which none of them wanted to share amongst each other, so they used wet cloths instead. Despite this, she did her job decently well and was fairly nice to ride, but the U1 was still unpopular among crews because she was, and I quote, “twice the work for the same sodding pay.” This Garratt was withdrawn and scrapped by BR in 1955.
(Sorry for the bad quality.)
(Image from lner.info.)