Crossing of the International & Great Northern Railroad and the Galveston, Harrisburg & San Antonio Railway
The International & Great Northern (I-GN) Railroad resulted from the 1873 merger between the International Railroad and the Houston and Great Northern Railroad. By 1881, they had completed a line from Palestine to Laredo via San Antonio. During this same period, the Galveston, Harrisburg and San Antonio (GH&SA) Railway was constructing a major east/west main line from Houston to El Paso. They had entered San Antonio from the east in 1877, and in 1881, they continued this construction west to Uvalde. By 1883, the entire "Sunset Route" across Texas would be complete. The I-GN line to Laredo and the GH&SA line to Uvalde crossed at grade in southwest San Antonio, but it was not until 1916 that an interlocking tower was constructed. From photos of Tower 105, it is apparent that the tower was a Southern Pacific (SP) design. The GH&SA had become controlled by the SP system many years earlier and it was eventually merged into the Texas & New Orleans (T&NO) Railway which was SP's principal operating railroad in Texas. In 1917, the Missouri-Kansas-Texas Railroad funded the construction of the San Antonio Belt & Terminal (SAB&T) Railway (and then leased it for 99 years) to provide switching services among railroads in the San Antonio area. The SAB&T had a track parallel to the Sunset Route between Tower 112 and Tower 105 where it connected to the I-GN.
Above: Henry O'Connor photo  from the collection of Tim O'Connor -- the view is looking northeast across the I-GN tracks in the foreground, with the diamond at left. A. Tyrrell Kott adds...
"Tower 105 was painted yellow and brown. This is the T&NO/SP paint scheme. Note that the moveable window sashes are white. The tower has brown screens that obscure this fact, but one window is open and you can see the white sash."
Above: John W Barriger III took this photo of Tower 105, probably in the late 1930s, from the rear of his business car as his train proceeded east into San Antonio. The view is west down the Sunset Route tracks. The I-GN crosses behind the tower; the foreground crossing track is the connector that allowed northbound I-GN trains to access the SAB&T, which paralleled the north side of the Sunset Route between Tower 105 and Tower 112. Below: Barriger took this photo of the tower on a different day, but in the same general timeframe. As in the above photo, it appears that the parking spot for the tower operator was across the tracks.
Historic Map, Tower 105
Above: Although Tower 105 was not constructed until 1916, it was added for the 1952 republication of the 1912 Sanborn Fire Insurance Map of San Antonio.
Above: The 1952 republication of the 1912 Sanborn Fire Insurance Map of San Antonio shows the location of Tower 105 on the south side of the crossing diamond. Magnification reveals that it was documented as a 2-story "Ry Watchman's Tower". The map shows that this crossing was adjacent to the Union Stock Yards stock pens, and that there was a connecting track located in the south quadrant. The map does not show the SAB&T connector; it had not been built when the map was initially drawn in 1912. The shed across from the tower is also missing, for reasons unknown.
Aerial Image, Location of Tower 105
Above: An aerial image of the Tower 105 location shows an SP connecting track in the southeast quadrant. The abandoned SAB&T connector can be seen as the light colored gravel road on the north side of the SP double track curving and ending at the tracks. Previously, it crossed the SP and connected to the I-GN at lower left. The photos show that the tower was trackside in the southeast quadrant; at various times, it had one or two connecting tracks behind it. Below: A ground view facing west shows the replacement Tower 105 equipment cabinet on the north side of the tracks. (Jim King, Sept. 2009)