Meant to add, and is indeed appropriate for another post.... Harty's influence in the "Bredins".
It was common practice in the past (and quite wrongly so, in my opinion) for the head of department to take credit for work he had overseen. Best example - all the bridges "built by" I K Brunel, or all the locomotives (personally?) built by Robert Stephenson, and did Gandon or Mulvany actually "build" all sorts of fine buildings?
Reality is, Bredin had a team of draughtsman, as did his predecessors and others like him. The most famous thing attributed to Bredin is of course Maedb and her sisters. If you examine drawings of these locos and indeed the "Bredin" coaches, you will not find the initials of Edgar Craven Bredin on them, you will find initials of others.
Not to dismiss Bredin by any means; he wasn't the head of the department for nothing. He oversaw, and I suppose as they say now "facilitated" the transfer from an idea, via a plan, to a running locomotive.
His Chief Draughtsman was also heavily involved in the accompanying coaches, the second batch of the Drumm Battery trains, and many locomotive rebuilds.