Construction crews have started to prepare the Eglinton Crosstown LRT's tunnel for its tracks.

The nine kilometre twin tunnel stretching from Black Creek Drive to Laird Drive has now been fully bored, but doesn't have an even floor yet.

Over the next weeks, crews will perform an "invert pour" in the tunnel, creating a foundation for the LRT tracks.

Metrolinx plans to lay down the new line's first tracks at the LRT's vehicle service station later this summer.

The line is scheduled to open in 2021 with 25 stations.

Here's a look inside the tunnel.