A large tower with buildings surrounding it. The tower tapers towards the top, but has a spherical section two thirds the way up. In front is a large road.

Rail Lands: CN and John St. Towers

The CN and John Street Towers

A large tower with buildings surrounding it. The tower tapers towards the top, but has a spherical section two thirds the way up. In front is a large road.
The CN Tower, Toronto, June 11, 2022.

The CN Tower, Toronto, June 11, 2022.

An orange helicopter flying over the top of a large tower. Attached to the helicopter is a piece of the tower.
Construction of the CN Tower’s antenna, Toronto, March 23, 1975. Courtesy of the City of Toronto Archives.

Construction of the CN Tower’s antenna, Toronto, March 23, 1975. Courtesy of the City of Toronto Archives.

Four men in construction outfits stand in front of a brown brick building with tan pagoda-shaped roof. In front of the building are a number of rail lines. A sign on the building reads "John St."

John Street Interlocking Tower with its original roof intact, Toronto, Circa 1980. Courtesy of the City of Toronto Archives.

A Small rectangular building made of brick. Some construction work is happening on the left side. There is a large pedestrian bridge directly on top of the building covered in flowers. In front of the building are rail tracks.
John Street Interlocking Tower, Toronto, June 25, 2022, Image by Brandon Corazza.

John Street Interlocking Tower, Toronto, June 25, 2022, Image by Brandon Corazza.

Toronto’s largest landmark

The Canadian National Tower, better known as the CN Tower, is perhaps one of Toronto’s most famous landmarks. Completed in 1975, the CN Tower opened to the public in 1976 and was the tallest freestanding structure in the world until 2007. To accommodate the growing number of large condos and apartments in Toronto, Canadian National (CN) constructed the CN Tower to allow for the continued broadcasting of FM radio stations in the downtown core. Originally, the tower was intended to be part of a joint telecommunications subsidiary of both CN and the Canadian Pacific Railway (CPR), but CPR pulled out of the project. Over 1,500 workers helped to complete the tower.

Today, the CN Tower is one of Toronto’s most popular tourist attractions, with over two million annual visitors. The tower also holds annual tower climbs to raise money for charity. To date, the fastest time to complete the climb the Tower’s 1,776 steps was 9 minutes and 54 seconds by Shaun Stephens-Whale in 2017.

Construction begins

Construction of the CN Tower was a huge task. Workers needed to excavate 56 tonnes of rock to make the massive foundation for the building. One of the scariest moments occurred near its completion in March 1975. To install the 335-foot antenna on the top of the tower, workers needed to use a helicopter. Workers nicknamed the helicopter Olga.

Due to stronger than normal winter winds, Olga became tangled in construction cables and supports. With only a few minutes of fuel left, her operator finally untangled the helicopter and landed safely. Workers eventually attached the antenna in April after waiting for better weather.

In the shadow of the giant

In contrast to the CN Tower, the John Street Interlocking Tower is rather unassuming. Located just west of the CN Tower, this brick building is one of several interlocking switch towers operated by the Toronto Terminals Railways (TTR) and controls the signals and switches for rail tracks leading in and out of Union Station. TTR built three interlocking towers along the corridor, with the other two located on Cherry and Scott Streets.

Similar to other railway towers, the John Street Tower is two stories tall with the interlocking mechanism located on the top floor overlooking the tracks. The tower only controls the interlocking for a small portion of the corridor. This 1.3-kilometre area spanned from the tower itself to just west of Spadina Avenue. Workers used a system of loudspeakers to communicate between the towers.

Interlocking at John Street

Interlocking is an important process in busy rail corridors and can be thought of like traffic lights for trains. To ensure trains move safely along the tracks, workers use a series of signals and switches to control the movement of the trains on specific tracks. While labourers constructed the towers, the movement of the tracks required 60 workers manning switches along the corridor.

When the John Street Tower opened, it housed approximately 170 switches that controlled the rail signals. This included a system lights, as well as the mechanism that moved portions of the tracks. As a safety precaution, if certain switches were tripped, they remained locked until the controller switched them in reverse order. One unique aspect of Toronto’s rail lands is that much of the 1930s interlocking system is still intact and, until recently, in daily use by tower controllers. 

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