Calgary Transit is buying 150 new diesel buses to replace aging ones and support increased ridership, officials say.

The 12-metre New Flyer buses will be built at the company’s facility in St. Cloud, Minn., starting later this year.

They will cost just under $400,000 each and be delivered by the end of 2014, officials said.

"With transit ridership steadily increasing year-over-year, there is a great need for us to increase reliability by replacing older buses and improve accessibility with more low-floor buses,” said Calgary Transit director Doug Morgan.

Calgary Transit has bought 653 buses from New Flyer in the last 20 years, most of them diesel.

It's currently testing natural gas buses to determine which company could supply those vehicles in the future.

Calgary Transit currently has 1,100 buses in its bus fleet.