Dozens of additional passenger train runs should be operating in southern Ontario later this year as Via Rail Canada continues its push to increase the frequency of trips in and out of London, Ont.

Proponents of increased passenger rail service got a glimpse of the company's expansion plans when Via tested a couple rebuilt diesel cars near Chatham.

Testing out the diesel cars sends a signal of Via's progress, according to Terry Johnson, president of the Southwestern Ontario Transportation Alliance.

The alliance has been advocating for increased passenger service for years.

"What we hear when we talk to people about what they would like to see done to make passenger service more attractive to use, frequency is a big factor," Johnson told CBC News.

Via Rail confirmed its plan to add dozens of trips in the region, including four extra round trips between Sarnia and London and several others trips out of Windsor.

VIA Rail diesel passenger cars

VIA Rail tests passenger cars for new southern Ontario runs. Tests were conducted between Chatham and Thamesville.

"For all the customers we have in the region, it would be great news because it would add frequency and flexibility for them to take the train," said Marie-Anna Murat, Via Rail's senior communications director. "A lot of people in the southwestern region travel a lot by train, if not commute every day. It would be great for us because it would mean our ridership would increase."

Murat said Via plans to use the recently tested diesel cars to increase the number of trips. The cars have a driving position at each end, enabling them to travel in both directions without being turned around.

"They would be ideal to operate in the region to supplement services until we receive further investment to move ahead and do things in a different manner," Murat said. 

Johnson caught wind of the diesel car testing on social media and headed straight to Thamesville to get a look.

He wants to see Via stick to its plans to increase the number of trains between Sarnia and London. Sarnia lost its midday trains back in 2011 and 2012 and are down to just one train a day.

"That's huge to actually turn that around from something that was basically [unused] to something that's actually providing quite a good service," Johnson said.