Robey Street Yard (Global 1) to Blue Island/Barr Yard

From Rockwell Street (MP 29.8), end-on junction with the Altenheim sub. and the north apex of the wye on the east side into the former Wood Street Yard  (now UP's Global I West), with a double track connection along the south side of that yard to the former Robey Street Yard (now UP's Global I East), that once served as the B&OCT's central Chicago yard and locomotive terminal, where an erstwhile line continues east to Grand Central Station, the line heads south, single track, maximum speed 10 mph, past the start of double track, current-of-traffic (Rule D-251), maximum speed 20 mph, at 14th Street (MP 29.5), the junction with the south apex of the wye from Robey Street (and formerly Grand Central), now used by NS (on the former Chicago Junction) for access to Global I at 16th Street (MP 19.4), a bridge carrying the former CB&Q overhead, with connectors in the southwest and southeast quadrants, a bridge carrying the CTA Pink Line overhead, the southeast quadrant connector finally trailing in, and crossovers at 22nd Street (MP 28.8).

There is a flat crossing with a former Santa Fe industrial line at 26th Street (MP 28.5), through-truss movable bridges over the Chicago River (second and third from the east of four through-truss movable bridges at this location), flat crossings with the IC Iowa line and former Santa Fe (with southeast and southwest quadrant connectors), at Ash Street (MP 27.8), where the maximum speed rises to 25 mph, a bridge carrying I-55 overhead, and a crossover at 35th Street (MP 27.6), a flat crossing with the IC Joliet Line at Brighton Park (MP 27.4), where the maximum speed rises to 40 mph and the crossings were controlled by a flagman until 2010, an angled bridge carrying the CTA Orange Line overhead, which then turns to run alongside to the west, a bridge over Archer Road, a bridge over Pershing Road, and a crossover at 39th Street (MP 27.0).

The NS (former Chicago Junction) Ashland Avenue Yard and then the GTW Railport Yard lie to the east, north of 43rd Street, where an additional tracks starts on the east side at around MP 25, past a bridge carrying an erstwhile Indiana Harbor Belt line and the Grand Trunk Western line (from Railport Yard) overhead, a crossover at 51st Street (MP 25.7), where CTC starts and the double track becomes Two Main Tracks, a bridge over 51st Street, an additional Main Track starting on the west side and more crossovers, still at 51st Street, MP 25, a bridge over 55th Street, crossovers among the Three Main Tracks at  59th Street (MP 24.8), MP 24, 59th Street Ramp Yard on the extra track to the east, a bridge voer 64th Street, the south end of that yard and a crossover from the extra track to the east at 71st Street, and Marlboro.

The Third Main Track and the extra track to the east end, and there are northeast and northwest quadrant connectors with the Belt Railway of Chicago at Belt Connection (MP 22.8), whose interlocking includes 71st Street, the flat crossings with the BRC and the Metra Southwest Line (four tracks total) at 75th Street (MP 22.5), maximum speed 35 mph in the interlocking, Track 3 begins again at the north end of Forest Hill Yard (six through tracks and four south-facing stub tracks) to the west, which ends at 79th Street (MP 22.0), where the maximum speed drops to 20 mph, the B&OCT bridges over 79th Street and jogs west, and a former B&OCT line (only a stub remains) once headed just east of due south, with Track 3 ending at CP 82nd Street (MP 21.6).

The line turns back to the south, past a crossover at  CP 88th Street (MP 20.8), grade crossings with 87th Street, 91st Street, 95th Street,  99th Street  and 103rd Street, north-facing Intermediate Signals at MP 18.9, a grade crossing at 104th Street, south-facing Intermediate Signals at MP 18.8, grade crossings at 105th Street, 107th Street, 109th Street, 111th Street, 113th Street and 115th Street, north-facing Intermediate Signals at MP 17.3, Tracy Avenue, south-facing Intermediate Signals at MP 17.2, Morgan Park, a jog south-southwest and then south again, a grade crossing at 123rd Street, a grade crossing at 127th Street, a jog just east of due south, past a grade crossing with Union Street, with the GTW alongside to the west, and then south again, past a grade crossing with Vermont Street, Intermediate Signals, and a through-truss bridge over the calumet Channel (easternmost of four at this location).

There are connections from the Indiana Harbor Belt, which crosses over the GTW at this point, from the west, and a crossover at Blue Island Junction (MP 15.0), where the maximum speed rises to 30 mph, a bridge carrying the Metra Rock Island Line overhead as the line turns east, a grade crossing with Western Avenue, a wye on the south side at Harvey Junction (MP 14.1), where the line to Harvey heads south, with a grade crossing with Chatham Street just east of the west leg of the wye, and crossovers at the east leg of the wye, a bridge over the Calumet River, crossovers at Roll Avenue (MP 13.9), the west end of Barr Yard (which is on the south side of the Two main Tracks, with I-57 bridging overhead, a bridge over Ashland Avenue, and a bridge over Halsted Street.