the nuisance of smoke in the tunnel created by steam locomotives prompted attempts by the railways department to alleviate the problem. in august 1909, they had locomotive wf 433 converted to oil burning to reduce the amount of smoke produced. the locomotive was used for a trial period to haul 450 ton goods trains through the tunnel. though the modification proved to be efficacious, the benefit did not outweigh the cost involved and the idea was abandoned.