The Brown Line begins on the northwest side of Chicago, at the Kimball terminal in Albany Park, where there is a storage yard and servicing shop for the trains to the east of the passenger station.

From there, trains operate over street level tracks between Leland and Eastwood Avenues to Rockwell, then ramp up to the elevated structure for the rest of the trip.

A fatal accident in 1977 involving an intoxicated man, who did not speak English and was unable to read the posted warning signage, attempted to urinate on the third rail at the Kedzie station eventually resulted in an Illinois Supreme Court decision in 1992 affirming a verdict of $1.5 million against CTA.

Another is the North Side Main Line which connects from Belmont Avenue station to the Merchandise Mart before entering the Loop.

In the meantime, CTA has completed the process of overhauling the 3200-series cars with color LED destination signs (similar to the 5000-series cars), new air conditioning systems, rebuilt propulsion systems, passenger door motors, and wheel/axle assemblies.

Traction power equipment and train control systems were upgraded and a new fiber optic communication network installed.

[11] Brown Line stations were rebuilt or modified meet ADA compliance and to accommodate eight-car trains, increasing from the previous maximum of six-cars.

Merchandise Mart was the only station not to receive any work as it had previously been reconstructed from 1987 to 1988, and was already ADA compliant and able to accommodate eight-car trains.

[15] The Red & Purple Modernization Project includes a redesign of a diamond junction north of Belmont Station into a flyover allowing Brown Line trains going north to circumnavigate crossings with Red and Purple Line trains.

[16] The project was criticized by 2015 mayoral candidate Chuy García and local residents in the Lakeview neighborhood who organized a referendum to stop it.

[19][20] Sixteen properties affected by the bypass were demolished, while the historic Vautravers Building was relocated 30 feet west to preserve it.