WW1 North British Railway NBR war service badge

A very rare original First World War period 'North British Railway gilt brass badge'; blue enamel title surround, red enamel Crowned 'Railway Service' to centre on white enamel ground, the reverse impressed with maker's details 'J.A.Wylie & Co London' and with official low issue number 'T 888'. Very good condition, complete with original buttonhole fitting, no damage to the enamel, very minor manufacturing flaws, an excellent example. Diameter 28mm.