Fireboxes were generally made of copper, though later locomotives had steel fireboxes.

The boiler is held onto the steel firebox with a single brass band.

Baldwin had built the class with round-topped steel fireboxes but the PR found these unsatisfactory.

Early conversions were equipped with copper and later conversions with steel fireboxes.

The boilers were given steel fireboxes and the frame was reinforced, especially in the area of the drive.

Twenty of the class, built in 1903, were fitted with Henry Hoy's corrugated cylindrical steel firebox.

It was 105 degrees down below, and a lot hotter in the steel fireboxes under the boilers.

Park grills - those sturdy steel fireboxes fixed to poles - are widespread.

In order to reduce the weight on the trailing wheels, steel fireboxes were used.

As was typical Hungarian practice, the first two locomotives were built with steel fireboxes.