Also known as “High-Flyers”, the Lancashire & Yorkshire class 7 locomotives were among the first Atlantics in Britain. Their nickname came from the high-pitched boiler that lay above the 7 ft 3 in high driving wheels. Aspinall had developed them to get a more powerful replacement for the existing 4-4-0 and 4-2-2 locomotives. As with Ivatt, this wheel arrangement was chosen to accommodate a larger, albeit narrow, firebox.
At the time of their introduction, they had the largest boiler of any British steam locomotive and reached high average speeds with the relatively light trains. While No. 1417's alleged speed of 117 mph is highly questionable, No. 1392 likely actually reached 100 mph with a five-car train on a trial run in 1899.
After one of the locos was the first in Britain to be fitted with an early superheater, five others were also fitted with it, but this was later removed. After the grouping, they were the only 4-4-2 tender locomotives on the LMS and were grouped into power class 2P. The withdrawals took place between 1926 and 1934.