North Eastern Railway 1906 2d yellow-green

North Eastern Railway, 1906 (Nov.) 2d yellow-green used on a 1907 1d stationery envelope to Co. Leitreim cancelled withblue crayon as usual, tied by a neat Belfast cds, with arrival backstamp of ENNISKILLEN / MR 7 / 07. Despite some small faults, all evidence points to this cover being commercial.
Ex Col. B. B. Zellers. DeLacy-Spencer #80.
This is a superb example of a triple transfer cover, being first transfered to the Glasgow & South 'Western Railway at Carlisle, then put onto the Stranraer/ Portpatrick to the Larne Packet (still outside the Royal Mail), then finally transfered to the Belfast & Northern Counties Railway.