Tower 105 to Centex, Track 1

Amtrak's Texas Eagle uses the former SP station in San Antonio (so it can connect with the Sunset Limited). With Union Pacific's acquisition of the M-K-T as well as the MoPac, it has chosen to operate the former M-K-T and former MoPac lines between San Antonio and Centex, just north of San Marcos, as paired track. Track 1 (the former MoPac, ex-International Great Northern) heads north-northeast from Tower 105 (MP 260.4), across the Sunset Route from the Union Stock Yards, on a 20 mph Yard Limits track, past Apache Junction (MP 259.9), a flat crossing with the former San Antonio and Aransas Pass line, SP until 1996, which has a connector in the east quadrant. This connector from the Sunset Route to the former MP is west of the former SP station, connecting at Tower 112. This means that a Texas Eagle heading for Track 1 must either head southward out of the station, taking the connector northwest from Tower 112 to Apache Junction, or run in reverse to Tower 105, taking the connector in the southeast quadrant by the stockyard and then pulling forward across the flat crossing at Tower 105.

The connector (UP Kerrville sub.) heads northwest from Tower 112 (MP 0.0), single track, Yard Limits, maximum speed 10 mph, with three or four yard tracks on the southwest side, past a spur on the south side, a grade crossing, an acute angled grade crossing (Proband Street), a grade crossing (S. Flores Street), an erstwhile flat crossing with the former M-K-T line to the erstwhile M-K-T station, all now gone, a bridge over a river, a grade crossing (S. Laredo Street), a road bridge overhead, a bridge over a divided road, and a road bridge overhead (all grouped together), and a grade crossing (Pecos Street), curving around to the north-northwest, past a grade crossing with Chicuahuah Street, for the (erstwhile) flat crossing with the former MoPac at Apache Junction (MP 1.6), with the connecting track to Track 1 on the east side.

From Apache Junction (MP 259.9), Track 1 heads north, still single track, Yard Limits, maximum speed 20 mph, past a road bridge overhead (Guadalupe Street), the three-track MoPac San Antonio Yard, extra track to the west, a street to the west (Salado Street), a road bridge overhead (Buena Vista Street), and the erstwhile MP San Antonio station (MP 259.1), at the north end of the yard, where the Yard Limits end in favor of single-track, CTC, and the speed limit rises to 45 mph, a grade crossing, a road bridge overhead, a grade crossing (Martin Street), signals and a junction with a line going off to the north-northwest, a grade crossing (Perez Street), a grade crossing (Leal Street), a grade crossing (Ruiz Street), San Marcos Street to the west, a grade crossing (Arbor Place), a grade crossing (Delgado Street), a grade crossing (Rivas Street), a grade crossing (Poplar Street), dual road bridges overhead (I-10), a spur to the west, trailing in, a grade crossing (Lambrano Street), a grade crossing (W. Laurel Street), a grade crossing (Gulebra Street), and a grade crossing with the angled Fredericksburg Road, with San Marcos Street still on the west side.

There is a grade crossing at Hickman Street, a grade crossing (Ashby Place), a grade crossing (Russell Place), a grade crossing (Craig Place), a grade crossing (W. Woodlawn Avenue), a grade crossing (W. Mistletoe Avenue), a grade crossing (W. Magnolia Avenue), a grade crossing (W. Summit Avenue), and a grade crossing at W. Kings Highway, and the line turns north-northeast past a grade crossing at Fulton Avenue and Intermediate Signals at Adams (MP 254.0), a grade crossing at w. Elsmere Place, a grade crossing at W. Hollywood Avenue, a closed grade crossing, a grade crossing at W. Hildebrand Avenue, a bridge over angled (N-S) Texas Street, a grade crossing with W. Olmos Drive, a grade crossing with Dora Street, a grade crossing with Zilla Street, a grade crossing with acute angled (N-S) McCullough Avenue, a grade crossing with E. Contour Drive, and exiting the urban area, past a bridge over a dirt road, a grade crossing with Basse Road,  northeast past a cutting, a wide angled (N-S) road bridge (McAllister Freeway) overhead, the 7,559 ft. east side siding at North Loop (MP 252.1-250.6), within which is extra track at Towne Spur (MP 251.8) and an angled grade crossing at Jones-Maltsberger Road.

The countryside north of San Antonio is lush farmland, since it is (just) east of the 100th meridian that represents the general boundary between the arid land to the west and the lusher land to the east. Also along the railroad between San Antonio and San Marcos are a number of rock quarries providing the kind of rock used in railroad construction and maintenance, as well as road building.

The line continues past Green Light Spur (MP 250.0), drainage to the west, a grade crossing with West Sunset Road, a spur to the west, quad road bridges overhead (I-10), Wetmore Road alongside to the west, Longhorn (MP 249.9, where there is extra track to the east and the Longhorn Industrial Lead trails in from the southeast, and Wetmore (MP 247.7), where the speed limit is 60 mph, turning east-northeast past a grade crossing with Bitters Road, a grade crossing with Broadway, Sentinel Street to the east and Wetmore Road still to the west, a spur trailing in from the east, a bridge over a dry wash, an angled bridge carrying Wurzbach Parkway overhead, a spur curving away east, making a wye with a spur traling in from the east, Wetmore Road still to the west, two bridges over dry washes, a grade crossing with Thousand Oaks Drive, a bridge over drainage, a grade crossing with Stahl Road, a spur trailing in on the east side, a dirt road grade crossing, an embankment, a bridge over drainage, a grade crossing with Jung Road, a bridge over drainage, a grade crossing with Classen Road, and three bridges over drainage.

There is a detector at MP 245.0, where the speed limit is 70-60, a grade crossing at O'Connor Road, a bridge over a dirt road, a grade crossing with Judson Road, a grade crossing with Green Mountain Road, dual road bridges carrying Texas 1604 Loop overhead, with access roads at track level on either side of the line, a grade crossing at Evans Road, a bridge over a dry river, a grade crossing with Farm to Market 2252, a bridge over a dry wash, and the 8,428 ft. west side siding at Bracken (MP 241.1-239.3), and a turn northeast, with a gated dirt track grade crossing and a dirt track grade crossing, plys extra track to the east, serving industry, within the siding, past a grade crossing with Doerr Lane, a grade crossing with Two Caverns Road, and two dirt road grade crossings, to South Schertz (MP 237.8), where there is a crossover to North Schertz on Track 2, a bridge over a dirt road, a bridge over drainage, a grade crossing wtih Farm to Market 2252, spurs on the north side at a rock quarry at Ogden (MP 236.7), and Craig Junction (MP 235.9), where a connector trails in from Ogden Junction on Track 2.

There is a 7,978 ft. west side siding at Corbyn (MP 235.0-233.4), where the speed limit is 60 mph, a dirt road grade crossing and a grade crossing within the siding, two bridges over roads, a sand facility on the east side, a grade crossing at the sand facility, sidings on the east side, a sand facility spur curves away to Track 2, a grade crossing, a closed dirt road grade crossing, the Western Railroad heads east at Dittlinger (MP 231.1), where the speed limit is 60-50, and the line turns east past two grade crossings, a road bridge overhead, two grade crossings, Brauntex (MP 230.8) and McCoy Lumber (MP 229.5), both places with additional tracks, to Landas Park (MP 227.8), where the speed limit is 30 mph for the flat crossing with Track 2 at New Braunfels (MP 227.7), where the line heads southeast past  a grade crossing just north of the flat crossing, four grade crossings in town, and a detector at MP 227.3.

The line turns turns north-northeast past two more grade crossings in town, a bridge over a street, a grade crossing, a bridge over a river, a plant on the west side, a grade crossing, Intermediate Signals at MP 225.6, a bridge over a road, a highway bridge overhead, two grade crossings, Coleman (MP 223.9), where the speed limit rises to 70-60, and a grade crossing, and northeast, just southeast of Track 2, past the 9,900 ft. east side siding at Goodwin (MP 223.1-220.9), a grade crossing, and Conrads (MP 220.7), where there is a crossover with Track 2.

At Jude (MP 219.0), there is a grade crossing and another crossover with Track 2, followed by a grade crossing, Hunter, a bridge over Track 2, which then curves and comes alongside to the east, a grade crossing, Intermediate Signals at MP 214.8, a grade crossing, and UP Junction (MP 212.0), where there is a track that connects back from Track 2 and a connector with Track 2 that trains headed for the former MKT line must take), additional track at H.E.B. (MP 211.6), a grade crossing, a road bridge overhead, a grade crossings, two bridges over streams, a grade crossing, and the platforms and shelters on the east side at San Marcos (MP 209.8 on Track 2), three grade crossings (the third is Glen Parkway), a bridge over a river, a grade crossing with a divided highway, and a grade crossing, before the final connector from Track 2 trails in from the south-southwest (i.e. the east side of the line) at the 8,249 ft. east side siding at Centex (MP 208.3, where the speed limit is 30 mph, past a grade crossing and a grade crossing at Pat Road, to MP 206.7, where it is 55-50), as the line heads north-northeast.

Approaching San Marcos, up on the hill to the west is San Marcos State University, its new high rises overshadowing the original two-story brick buildings where LBJ went to college and performed chores for the college president in return for lodging and board.