 The sides of the outside cylinders consequently sloped inwards towards the top in a configuration similar to GWR 2-cylinder locomotives, thus providing ample space in which to accommodate the extension levers.The inside cylinder and conjugation assembly were set at an incline of 1 in 8 to clear the front pony truck, leaving space for a third set of independent Walschaerts valve gear between the frames should Holcroft’s conjugation mechanism prove unreliable in service.Another issue concerned the strength of the locomotive frames around the cylinders.