Express service operates from Third Avenue – 138th Street to Parkchester during weekdays from approximately 6:30 a.m. to 8:45 a.m.. At those times, Pelham Bay Park cannot handle the large number of 6 and <6> trains in service. As a result, 6 trains run local on the Pelham Line south of Parkchester and terminate there. The <6> trains run express using the center track from Third Avenue to Parkchester in the peak direction and local from Parkchester to Pelham Bay Park. At all other times, 6 trains run local on the entire line.
The train that is hijacked in the book The Taking of Pelham One Two Three by Morton Freedgood (writing as John Godey) and the three films based on the novel originated on this line from Pelham Bay Park at 1:23 (hence the name "Pelham 123"). It was subsequently hijacked on the IRT Lexington Avenue Line.