A record-breaking number of people rode the UP Express on Saturday; the service has been free this weekend.

Metrolinx says more than 10,000 people rode the train, which runs between Union Station and Pearson Airport.

"Yesterday's numbers were outstanding. We couldn't be happier," company spokeswoman Anne Marie Aikins said.

She acknowledged that the main reason the numbers were so high was because the service was free. She said they offered the service for free to try to introduce more people to it.

Ridership has been very low with most trains operating at 90 per cent empty.

People lined up for the train service on Saturday. (CBC)

"A lot of people don't know where it is, what it is, how it works, whether its for them," she said. "It couldn't be a better weekend. In spite of the frigid temperatures, people came out in droves."

Aikins said the cold weather did cause one of their rails to break in the morning, but that was resolved shortly after.

She said the free weekend is part of their strategy to get more people to ride the train.

One of the main issues with the service has been the price: it costs $27.50 for a one-way adult ticket, and $19 with a Presto fare card.

She said they're looking at all of the barriers to ridership, including the price, and are considering whether to change it.

"We're also looking at better signage, better connections between our other service providers — GO, and TTC — so we're working on all of that and we'll be coming out with a new strategy in the coming weeks and months," she said.