Sen. Dick Durbin continued pressure on the Canadian National Railway Thursday, asking federal regulators to visit Illinois and witness delays on CN-operated tracks.
"These large-unit trains and other freight trains are blocking crossings and increasing delays," Durbin wrote U.S. Surface Transportation Board Chairman Daniel Elliott.
However, CN officials disagreed, explaining that delays at crossings earlier in the year were weather-related and are improving.
In 2008, the transportation board approved CN's purchase of the EJ&E Railroad, a small freight line with tracks that run from Waukegan to Joliet through the north, northwest and southwest suburbs.
Board members agreed with CN that using the EJ&E tracks would ease freight traffic in Chicago and on other railroad lines so trains could move quicker through the region. It imposed numerous conditions on the railroad, including a six-year monitoring period.
Communities including Barrington and Aurora fought the plan, noting it would put more freight trains in their towns, resulting in more traffic, noise, delays and environmental problems.
There were 5,267 cases of blocked crossings lasting 10 minutes or more between January and March, Durbin told Elliott, adding it was "the highest number since CN took ownership of the rail line.
"I believe it is important for you to visit these communities and hear their ideas about how the STB can ensure CN is operating safely," Durbin wrote.
CN spokesman Patrick Waldron said delays of 10 minutes or more in June were down 14 percent from May and 33 percent from March.
CN, like other rail carriers in the region, experienced delays in the first quarter of the year due to the polar vortex and other harsh winter conditions, railway officials said.
Durbin has suggested that the transportation board extend the monitoring period, which expires in January 2015.
He also asked the transportation board to scrutinize Amtrak delays on the Chicago-Champaign-Carbondale route. Those tracks are owned by CN.