It has been more than nine years since the Toronto City Council approved the Scarborough subway extension project and now construction has begun.

The tunnel boring machine, named “Diggy Scardust” was launched in January where Metrolinx officials have said that the machine will create a single subway tunnel with a diameter of 10.7 m (35 ft), which will be large enough to accommodate trains travelling in both directions.

The TBM will advance about 10 m (33 ft) each day, the officials say, with crews using a belt conveyor to transport soil and rocks back to the launch shaft site, CP24 reported.

“Today, we have hit another major milestone in delivering this much-needed project. Diggy Scardust, the largest tunnel boring machine ever used for a transit project in Canada, has started tunnelling,” a spokesperson for Minister of Transportation Caroline Mulroney told CP24.

The 7.8-km (4.8 miles) subway extension is likely still years away from completion with the latest timeline suggesting that it won’t be operational until 2030.

The project is expected to host 105,000 daily boardings including 52,000 daily boardings from new users. The project will include improved access to transit and jobs while reducing yearly gas emission by 10 kt (11,000 st).

The City of Toronto has said that it will shut down the Scarborough RT next fall due to the significant costs associated with maintaining the aging rapid transit line.

A portion of the Scarborough RT’s right-of-way will be turned into a dedicated busway to help provide supplementary service until the completion of the subway extension.

But that project could take until late 2025 to complete, according to the TTC.

The Scarborough RT opened in 1985. It was initially supposed to be replaced by a light rail transit network that would have been completed in 2020 but that project was cancelled under the leadership of former Mayor Rob Ford in 2010.

The Ministry of Transportation says that the new Scarborough subway extension will accommodate over 100,000 daily trips once complete.

Photo Credit: Metrolinx