Vintage Mammoth, Cock of the North Jigsaw puzzle

A rare jigsaw puzzle of Jigsaw, Mammoth, Cock of the North locomotive from 1930. The box is nice to see, especially if you like trains! The Jigsaw, Mammoth, Cock of the North vintage jigsaw puzzle is in good condition, the puzzles are specially made for children, made with permission from, by kind permission of the L.N.E., R.L.V. Co. We have not been able to find exactly what these letters stand for.