From Storrs Junction (MP 2.5), where there are connections between the former Big Four (now Indiana & Ohio Railway) and CSX (former B&O) St. Louis line, with River Road along the north side of both track formations, the CSX line continues southwest, curving around to the west along the north bank of the Ohio River, double track, current-of-traffic (Rule D-251), speed restriction 25 mph, past the end of double track at CW Cabin (MP 6.7), the end of Yard Limits in favor of Direct Traffic Control, Automatic Block Signals, at MP 6.8, the start of the St. Joe Block, and the end of the speed restriction in favor of a 50 mph maximum speed at MP 7.0, turning northwest, west, and north-northwest, all following the north bank of the Ohio River, past the end of the St. Joe Block and start of the Delhi Block at MP 10.0 and Delhi (MP 10.5), a 35 mph speed restriction from MP 13.1 to MP 15.4 as lines and river bank turn west.
The former Big Four line turns away north at North Bend (MP 15.1), and the former B&O remains on the north bank of the river as it turns southwest, past the start of double track, DTC, ABS (current-of-traffic) at MP 18.1, where the Delhi Block ends and the River Blocks (one for each track) start, and Finney (MP 18.3), turning west-southwest past Miami Fort, a bridge over the Great Miami River from Ohio into Indiana, Elizabethtown, the resumption of single track (15 mph on the switch), DTC, ABS, the end of the River Blocks and the start of the Nebo Block at MP 21.5, a 15 mph speed restriction through Lawrenceburg, from MP 21.6 to MP 22.5, Dearborn (MP 21.7), where an erstwhile branch from the Big Four line once crossed from the north to the south, and Lawrenceburg (MP 22.1), where that erstwhile branch crossed back to the north side.
There is a detector at Nebo (MP 24.2), a 25 mph speed restriction through Aurora, from MP 25.4 to MP 27.0, and Aurora (MP 25.8), where the Ohio River turns south and the line turns away curvily west, with a 40 mph speed restriction from MP 27.0 to Cochran Junction, past Cochran (MP 27.3) and the start of double track, the end of the Nebo Block and the start of the Dill Blocks at Cochran Junction (MP 30.3), where the maximum speed rises to 60 mph, but local restriction 40 mph on both tracks, to Dillsboro (MP 33.9), where the line turns curvily just west of due north, past Cold Springs (MP 37.6) and Moores Hill, turning just north of due west past MP 41.5, where the 40 mph restriction on Track 1 ends and full line speeds prevail on that Track and the resumption of single track (25 mph on the Track 2 switch), the end of the Dill Blocks, and the start of the Milan Block at Milan (MP 42.6), where a 2,300 ft. south side siding starts and full line speeds prevail.
The line edges gradually around to the west, past Pierceville, a detector at "Delaware" (MP 46.8), Delaware, and a 45 mph speed restriction from MP 48.8 to MP 49.2, turning south-southwest, with a 35 mph speed restriction through Osgood, from MP51 to MP 52, past a 6,850 ft. north side siding at Osgood (MP 51.5), where the Milan Block ends and the Osgood Block starts, turning west-southwest, past Dabney and Holton, a 45 mph speed restriction from MP 60.7 to MP 60.9, Nebraska (MP 61.5), a detector at "Butlerville" (MP 64.3), the 14,550 ft. north side siding at Butlerville (MP 65.6), where the Osgood Block ends and the Butler Block starts, and Oakdale, and then curvily before turning briefly south-southwest, with a 45 mph speed restriction from MP 69.3 to MP 71.5, and then west.
There is a 25 mph speed restriction through North Vernon, from MP 71.5 to MP 73.1, past the start of Yard Limits at MP 72.0, where the Butler Block ends, the flat crossing with the Madison Railroad (a former PRR line south to Madison, on the Ohio River, that once continued north but no longer does so) and the erstwhile flat crossing with the no-longer-extant Big Four line to Louisville, at North Vernon (MP 72.2), where an 11,644 ft. north side siding starts, the end of the siding, and of Yard Limits, at MP 74.1, where the Hayden Block starts, a turn southwest and then just south of due west, a detector at "Hayden" (MP 83.0), and a gradual curve west-southwest, past the start of Yard Limits and a 5,600 ft. south side ("East") siding at MP 85.0, where the Hayden Block ends, a 25 mph speed restriction through Seymour, from MP 86.2 to MP 88.2, and Seymour (MP 87.2), end of a 5,800 ft. north side ("West") siding, which overlaps with the "East" siding.
The former PRR Indianapolis-Louisville line, now run by Louisville & Indiana Railroad, makes a flat crossing with the former B&O at IO Tower (MP 87.3), and the latter continues west-southwest, past the end of Yard Limits at MP 89.0, start of the Dunham Block, the end of the Dunham Block and start of the Vallo Block at MP 97.0, a 40 mph speed restriction from MP 97.5 to MP 99.9 as the line becomes curvy, the 3,300 ft. south side siding at Brownstown (MP 97.8), a detector at "Vallonia" (MP 101.7), a 35 mph speed restriction through Medora, from MP 105.2 to MP 105.8, and the 9,000 ft. south side siding at Medora (MP 105.4), end of the Vallo Block and start of the Medora Block, turning curvily west, with a 45 mph speed restriction from MP 108.7 to MP 112.7, past Sparksville and Fort Ritner, a 40 mph speed restriction from MP 112.7 to MP 113.2 through Big Tunnel, where the line turns northward, just briefly, before turning curvily west again.
There is a 45 mph speed restriction from MP 113.2 to MP 119.1, past Tunnelton, the end of the Medora Block and start of the Spark Block at MP 117.7, a 35 mph speed restriction from MP 119.1 to MP 119.9, a 45 mph speed restriction from MP 119.9 to MP 125.8, a detector at "Rivervale" (MP 120.7), where erstwhile branches once trailed in from the south and left to the north, turning just west of due south, southwest and then just south of due west, past the start of Yard Limits and end of the Spark Block at MP 124.8, a 30 mph speed restriction through Mitchell, from MP 125.8 to MP 126.7, the 10,900 ft. north side siding at Mitchell (MP 126.4), end of Yard Limits, and a flat crossing with the former Monon line from Chicago to Louisville, which now only reaches as far north as Bedford.