CHICAGO (CBS) — Metra BNSF line passengers say they were roasting on the rails because of air conditioning problems.

CBS 2’s Vince Gerasole reports Metra switched to a new safety system last month, which changed the schedule and rider patterns, resulting in crowded train conditions.

Metra is trying to get an accurate rider-count to adjust the schedule even more, but broken air conditioners are making the problem worse.

On weekdays, 64,000 commuters step on board Metra’s most popular and challenged run.

“This line has grown and grown and grown over the years and we’ve completely saturated the line,” said James Derwinski, Metra’s CEO and Executive Director.

Since altering schedules for a new safety system, riders are dealing with even more crowded trains and broken air conditioners. Metra managers say they know they have a problem.

“I have literally heard more in the last 30 to 60 days about disgruntled passengers than I have in the last five years I’ve been on board,” said John Zediker of the Metra Board.

“Right now, our key focus has to be getting rid of the hot cars,” Metra’s CEO explained.

The BNSF line has 211 train cars. 5% of the train cars are experiencing chronic air conditioning problems and most of the cars those are over 30 years old.

The average car carries about 140 passengers and has two air conditioners, one on each side. If one of those is broken, Metra still keeps the car in service, otherwise passengers onboard will be forced to make their way onto other already-crowded cars.

Because of the age of those cars, it can take 10 days to replace the air conditioning system. Metra wants passengers to know a shortage of trained electricians adds to the blockage.

“We are moving cars around. We are doing things in the middle of the night to alleviate the problem. Right now, we are trying to get over the hump,” Derwinski said.

Metra says they are working on the problem, but says it may be weeks until it is resolved.