No person shall open the surface of any street, alley or way of the Municipality or shall make an excavation so near the line of any street, alley or sidewalk so as to endanger public travel, unless a permit is obtained for that purpose in the manner described in this article; provided, that it shall not be necessary for the corporate authorities of the Municipality to obtain a permit or for any railway company to obtain a permit for the purpose of repairing the roadbeds of its railway or the pavements between its tracks and one foot outside thereof, where such railway company shall repair and keep in repair that portion of the highway.