LONDONDERRY RAILWAY - 21 - 0-4-4T - built 1895 by The Londonderry Railway - 10/00 to NER No.1712 - 1909 withdrawn. The Londonderry only ever owned the one 0-4-4T and I think that this may be the same loco as in the other picture before it was reboilered with the tanks shortened. Note the two sets of buffer beams, the inner one to allow it to work with chaldron wagons.
The Londonderry Railway, located not in Ireland but the North East of England, was wholly owned by the Marquis of Londonderry to move coal from his numerous coalmines to the staithes at Sunderland and, eventually, from his own deepwater port at Seaham. The mainline ran from Seaham to Sunderland and carried not only goods but boasted a regular passenger as well. In July 1900, it was bought by the NER for £400,000.