Provided that no such requisition shall be made unless in the opinion of the Commissioner it is necessary or expedient for the construction of the proposed building or the safe enjoyment thereof that the pipe or drain should be closed, removed or diverted.

Railway administration to be informed in certain cases : If the Corporation desires to

place or carry any pipe or drain or do any other work connected with the water supply or drainage across any railways line, it shall inform the railway administration who may execute the same at the cost of the Corporation.