My input is that the horse is not big enough to pull a coal cart; it's more the size for a 'pony and trap'.
My own grandfather was a blacksmith-and-farrier and he used one to go to outlying farms.
Hi rancegirl,
This looks like a cob to me and they are much stronger than they look, my estimation about 14.2hh possibly 14.3hh Welsh cob
I am going by the adult holding the baby and the man holding the animal. although the head looks a little fine. I reckon it would be capable of pulling a cart.
I have driven ponies like these in carts.
Rabbit B
