As Covenantor said it is a GWR 0-6-0 PT.
They where used for light goods and branch line work.
Some where rebuilt saddle tanks other where built as is.
There where ,no exaggeration, hundreds of them built.
24 of them are still known to be in existence.
Kids love them from the Railway story books.
Droid image made your original post look like a painting/illustration...until I zoomed in. Outstanding photography!