The two P1s were only ever used between New England and Ferme Park, the only route deemed suitable for them by the Operating Department. In practice there were issues with running such large trains with such powerful engines. The large three-cylinder engines required a considerable effort on the part of the fireman and the booster was known as particularly hungry for steam requiring even more coal. As a result turns firing the P1s were considered as ones to avoid. It was also found that the heavier trains that the P1s could handle were too long for many of the passing loops resulting in delays to passenger trains. The result was that they were considered uneconomic as they were generally used in hauling trains of less than the for which they were built. In 1934 No 2394 was experimentally tried on the 07.45 am semi-fast passenger train from Kings Cross to Peterborough as part of the planning stage for P2 class locomotive 2001 "Cock o' the North". Although the engine was able to reach a maximum speed of , this put too much stress on the fireman who later commented that he was thankful not to have been going beyond Peterborough.