Why does 1522 make a chugging noise when it operates, especially when just starting up?
While the noise comes from the smoke stack, the reason behind it starts back at the firebox. Large quantities of fuel have to be burned to generate the heat needed to boil the water. If no outside air draft were present, the fire would starve for lack of oxygen. So, a draft is created by ejecting the used exhaust steam from the cylinders up the smokestack. As the steam expands up the stack, it creates a vacuum as well as making that ‘chugging’ noise. This vacuum pulls the exhaust gasses from the firebox through the boiler flue pipes up to the smoke box and out the stack, which creates a draft inside the firebox to draw in more outside air.Now, to REALLY complicate the issue, you will notice that the 1522 is REAL loud when first starting up. That is because the locomotive is using full boiler pressure to start up – essentially a straight pipe from the boiler to the cylinder.
While the noise comes from the smoke stack, the reason behind it starts back at the firebox. Large quantities of fuel have to be burned to generate the heat needed to boil the water. If no outside draft were present, the fire would starve for lack of oxygen. So, a draft is created by ejecting the used exhaust steam from the cylinders up the smokestack. As the steam expands up the stack, it creates a vacuum as well as making that ‘chugging’ noise. This vacuum pulls the exhaust gasses from the firebox through the boiler flue pipes up to the smoke box and out the stack, which creates a draft inside the firebox to draw in more outside air. Now, to REALLY complicate the issue, you will notice that the 1522 is REAL loud when first starting up. That is because the locomotive is using full boiler pressure to start up – essentially a straight pipe from the boiler to the cylinder. Comparatively little steam expansion takes place before the valve closes the cylinder and the piston reaches the end
