Water Gauge

What is this then!!! This glass tube is a water level indicator, this shows how much water is currently in the boiler, this particular glass is backed with a red pigment to make the water level easier to see.

There is one on each side of the regulator and they should both match, if they don’t a reading should be taken from the highest.

Water is one if not the most important thing to keep a check on when steaming a locomotive.