4-4-0 Boiler shape

Hello all,

In the uploaded attachement of a scaned picture of an 1875 built 4-4-0 named "Old Molly", the boiler to me appears to be of one diametre along it's full length. My question is, is it or not? Also is ther a site on the net that would either or both , have a pictorial list of this type of wood burning 4-4-0?

Take care,

Jim Marsh Sr.

Some of these boilers were the same diameter from front to back. Others, notably the "wagon top" design, increased in size toward the rear, biggest diameter under the steam dome. The boilers were limited in size due to the narrow fireboxes and resulting smaller heating surfaces. In other words, a small firebox couldn't keep a big boiler under steam for very long.

No idea if there would be a website somewhere listing all 4-4-0 boilers like you asked.