Also, the skyline casing, which was fitted at the top of the boiler, proved to be a trap for soot from the locomotive's exhaust. Consequently, these began to be removed from some examples of the class, leaving them with just the bullet nose.
This led to the removal of the crowning feature, which was installed at the top of the boiler, as it became a source of trouble by trapping soot from the locomotive's exhaust. Consequently, some examples of this class began to have their crowning features removed, leaving them with just the bullet nose.