By Vince Gerasole

CHICAGO (CBS) — Metra users are used to alerts after a week full of weather-related schedule changes, but commuters will start hearing a new message that might cause some confusion, and has nothing to do with the weather.

Metra is implementing Positive Train Control, a computerized system designed to help prevent crashes, and hopes to have the $400 million system installed on all its rail lines by the end of next year.

But working out the kinks can sometimes cause delays and confusion.

As Metra rolls out PTC on line after line, sometimes it can cause delays. Announcements meant to let riders know what happening admittedly need a little explaining.

“Your attention please, inbound train number 400 is operating 15 to 20 minutes behind schedule due to Positive Train Control issues,” one such announcement states.

Metra chief operating officer Bruce Marcheschi acknowledged most people probably don’t really understand what the announcement means.

“We are going through growing pains just like every other railroad – whether a commuter railroad, a freight railroad, or a passenger railroad – in this entire country,” he said.

Positive Train Control is a federally mandated computerized safety system designed to prevent crashes.

“The system software that operates Positive Train Control is very, very complex,” Marcheschi said.

PTC monitors a train’s weight, speed, and track conditions; taking control of the train – even stopping it – if for some reason the engineer is going too fast, or has the train too close to another vehicle. That can cause delays.

“As you can imagine, software does have bugs, and once you start operating something, you start to work those bugs out,” Marcheschi said.

Metra said PTC sometimes kicks in because of a glitch in the software, causing an engineer to stop the train and reboot the system mid-run. That takes time.

“It’s a learning curve,” Marcheschi said.

PTC had a rough roll-out last summer. The system increases the time it takes to flip a train for its next run by about 10 minutes. Debuting on the BNSF Railway line, it meant adjusting almost the entire schedule, which led to more crowded trains as riders adjusted.

The system now is being used to varying degrees on BNSF, Rock Island and UP trains.

On weekdays, Metra runs 686 trains, and PTC is operational on about 30 percent of them, but that number represents about 50 percent of all Metra commuters.

Metra believes, as engineers become more familiar with the system, troubleshooting the glitches will take less time.

Rail systems throughout the nation must have PTC systems fully operational by the end of 2020.

Vince Gerasole