Shawn Carlson is a German physicist.
-RCB-. |  -RCB-. milepost markers from except * estimated from. |  -RCB-. The San Pedro and Southwestern Railroad is an Arizona shortline railroad , currently operating from a connection with the Union Pacific Railroad -LRB- UP -RRB- at Benson , Arizona , seven miles to Curtiss , Arizona .. Curtiss. Curtiss, Arizona. San Pedro. San Pedro, Arizona. Arizona. List of Arizona railroads. shortline railroad. shortline railroad. Union Pacific Railroad. Union Pacific Railroad. The SPSR formerly ran a total of 76.2 mi , with main track from Benson to Paul Spur , a location about 10 mi west of Douglas , as well as the Bisbee Branch which ran 5.6 mi to Bisbee , Arizona .. Bisbee. Bisbee, Arizona. Douglas. Douglas, Arizona. Arizona. List of Arizona railroads. The SPSR is owned by David Parkinson 's `` Arizona Railroad Group '' .. Arizona. List of Arizona railroads. David Parkinson has owned several other shortlines in California , such as the California Northern Railroad , under his ParkSierra Rail Group , now a part of RailAmerica .. California Northern Railroad. California Northern Railroad. RailAmerica. RailAmerica. The San Pedro and Southwestern Railroad commenced operations in November 2003 when it purchased the San Pedro and Southwestern Railway from RailAmerica .. San Pedro. San Pedro, Arizona. RailAmerica. RailAmerica. David Parkinson acquired the line from RailAmerica in 2003 with `` the intent of restoring transborder rail service with the Mexican rail system at Naco , Arizona , and developing North American Free Trade Agreement-related traffic , but that this plan never materialized . ''. Naco. Naco, Arizona. Arizona. List of Arizona railroads. RailAmerica. RailAmerica. North American Free Trade Agreement. North American Free Trade Agreement. SWKR 's traffic was weak and consisted of coal and coke for Chemical Lime , the only on-line shipper .. Chemical Lime only generated between 380 and 500 carloads per year which SWKR claimed was inadequate to sustain the railroad .. SWKR decided to abandon the line south of Curtiss in March 2005 due to limited freight business and the lack of prospects for future traffic increases .. Curtiss. Curtiss, Arizona. On February 3 , 2006 the Surface Transportation Board -LRB- STB -RRB- authorized abandonment of the line -LRB- STB Docket #AB -1081 -0 - X -RRB- .. Surface Transportation Board. Surface Transportation Board. However , on February 13 , 2006 , Sonora-Arizona International LLC filed an offer of assistance with the STB , to acquire the line for $ 5.6 million .. Arizona. List of Arizona railroads. Sonora-Arizona International LLC. Sonora-Arizona International LLC. On July 18 , 2006 , the Cochise County Board of Supervisors declined to write a letter suggesting the line be converted to a trail , saying investors should be given sufficient time to arrange reactivating the line .