Ever wondered why the subway slows down between Summerhill and St. Clair station? The National Post has the answer:

They call it the “Summerhill Slowdown.” The Toronto subway will be humming southbound along the Yonge Line when suddenly, right around St. Clair station, the entire train will slow to a maddening 15 kilometres an hour – slightly faster than the top speed of a chicken. During rush hour, the effects of the slow zone are magnified as trains are backed up around the slow zone waiting their turn. At peak hours, seasoned travelers report losing as much as ten minutes on their commute each way.

The reason? A lack of gravel on the tracks. On many sections of the Toronto Subway, the tracks are installed the same as they would be for a commercial freight line: The tracks rest on railway ties, and the railway ties are held in place with tamped down gravel – or “ballast” in railroad jargon. There is no ballast on the tracks between Summerhill and St. Clair. As a result, a train travelling at full speed could shake the line apart.

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