Paragraph 11

The Executive shall give to Railtrack not more than six months' and not less than 28 days' notice in writing of their intention to commence the construction of any of the specified works and, except in case of emergency (when they shall give such notice as may be reasonably practicable), of their intention to carry out any works for the repair or maintenance of the specified works in so far as such works of repair or maintenance affect or interfere with railway property.