Four-car trains are now running on the blue line of Calgary's LRT system.
Mayor Naheed Nenshi said half a dozen four-car trains will run each weekday between the Saddletowne station in the northeast and the 69th Street station in the west.
The longer trains can carry 200 more passengers per trip than the three-car trains.
"It's a major improvement that will alleviate overcrowding on trains and provide more comfort for customers, especially during rush hour," the mayor said.
Calgary Transit director Doug Morgan said the city has so far received 19 of more than 60 light rail vehicles (LRVs) it ordered from Siemens, as part of a $200-million contract.
Dozens more cars are due to be built and delivered to the city over the next year and a half, further expanding the availability of four-car trains.
Nenshi said two more LRVs are due to arrive this week.
"As they come, they get added to the system," the mayor said.
"So what we will see eventually, once they are all in, is we'll see the majority if not all of trains being four cars."
Morgan said between eight and 10 four-car trains currently run on the Red Line between the Tuscany station in the northwest and the Somerset-Bridlewood station in the south.
About half of the new LRVs will be used to expand the fleet while the other half will replace older vehicles.
The oldest of the C-Train cars have been in service for 35 years.
Morgan said it will probably be about two years before all the C-Trains operating in Calgary are four cars long.