A Missouri Pacific railroad junction
Tower 215 in Bloomington has the distinction of being the last numbered interlocker in Texas. Bloomington first became a junction of two rail lines when the St. Louis, Brownsville & Mexico (SLB&M) Railway opened a 38-mile branch to Port O'Connor on March 1, 1910. This line departed to the southeast from the main line that had been built through Bloomington when the SLB&M completed construction between Refugio and Bay City in 1905-06. Bloomington gradually became a full fledged town that began to grow when the Port O'Connor branch was built. A few years later, SLB&M completed a 14-mile branch from Bloomington northwest to Victoria. Charles Zlatkovich, citing Railroad Commission of Texas (RCT) records, lists this construction as occurring in 1915, but the Handbook of Texas says 1912. In 1925, SLB&M became part of the Missouri Pacific (MoPac) Railroad, but the SLB&M name continued to be used until MoPac further consolidated its various railroad holdings in 1956. Today, MoPac successor Union Pacific operates the lines through Bloomington. The branch to Port O'Connor was abandoned between Seadrift and Port O'Connor (1933) and between Long Mott and Seadrift (1969). It remains in place to serve chemical plants between Bloomington and Long Mott. Tower 215 appears to have been an automatic interlocking system commonly used in the 1960s. Almost certainly there was never a tower structure there. The commissioning date is unknown but it is likely to have been around 1966.
Vintage Photo, SLB&M Depot in Bloomington (courtesy Ken
Tower 215 is also the appropriate end to an RCT policy established in the 1920s. Originally, the RCT numbered interlocking system was intended to manage the development of safer, more efficient grade junctions where two or more railroad companies were present. By the early 1920s, RCT policy-makers had begun to reinterpret their legislative mandate to include responsibility for authorizing and approving interlocking systems in railroad yards and junctions that involved only a single railroad. The earliest evidence of this change in policy was with the approval of Tower 117 in Houston, a tower that involved only the Houston Belt & Terminal railroad. However, it is likely that Tower 117 would have received an RCT authorization anyway because it was constructed as part of a larger plan involving Tower 116 which supported multiple railroads at Houston Union Station. Within a year of Tower 117's approval, Tower 121 was authorized as a single-railroad yard tower in San Antonio. Authorization for Tower 215 was probably sought because the junction was upgraded to an automatic interlocker. It appears that RCT policy did not require legacy single-railroad interlockers to be authorized and numbered until they were upgraded.
Thus far, RCT documents citing the reasons for terminating the numbered interlocking system have not been located. It seems likely that the rapid pace of technological change associated with signaling and safety that occurred in the 1960s may have led RCT to conclude that their mission to approve and manage interlocker design was duplicative of Federal safety efforts. Whatever the case, it was a Missouri Pacific Railroad interlocker at Bloomington to which the Tower 215 nomenclature was assigned as the last numbered interlocker in Texas.
Bloomington Junction Photos, December 2006 (Jim King)
Above: Facing southeast, the branch line from Victoria connects to the UP main line in both directions.
Below: Facing northwest, the former branch from Port O'Connor connects to the UP main line to the north.
Satellite Image, Bloomington Junction
This satellite image shows the branch lines to Victoria and Long Mott to be in alignment across the UP
main line. Presumably a diamond connected the branch lines directly at one time.