WR also covered Road and Quarry companies. In topo's case, however, the WR/26... number suggests a Railway company, but I don't think it's possible to tell which one.
Some similar numbers from the pension records:
WR/269118 - 22nd Light Railway Operating Coy
WR/269152 - 261st Railway Construction Coy
WR/269237 - 21st Light Railway Train Crews Coy
WR/269331 - 9th Light Railway Operating Coy
Did he work on the railways before/after the war?
Adrian