clkayleib: CB&Q 300 1-69
rivannarailfan: "Clear" N&W RY Signal SAS Coling, VA
MP 142, CG Tower: Slow Down...look around...
MP 142, CG Tower: Aurora 2024, Approach Slow
railfan 44: Roger Puta in Nebraska -- 8 Photographs from May 1980
Wang Halen: StupidFleet
Leo Blackwelder: Not All Bad
sbhrs: Smithsonian Interlocker
wccnds John Leopard: NS-VGN signals Patrick Henry - Brookneal, Virginia2_
brian.m.rule241: The United States Signal Co. Type K signal , Newton Mass.
Tim Boric: Tram interurbano in Milano
MP 142, CG Tower: Restricting, DT&I Junction
sullivan1985: HX Tower Operators Floor
Erik Landrum: C&O / CSX KC Cabin at Covington, Kentucky on February 4, 1989
sbhrs: Switch Interlocking Machine
en tee gee: Interlocking Machine
luxomni: Armstrong Interlocking Machine
Adam Klimchock: BECK Tower Interlocking Machine; Becks Run, PA; July 1985
d.w.davidson: Chicago & North Western - Chicago Passenger Terminal
rivannarailfan: N&W RY Signal at W.E. Dawson, WV
rivannarailfan: EAS Virginia Lee, VA
rivannarailfan: E14214 - CSXT 3236 East at W.E. Hartland, WV
rivannarailfan: E14214 - CSXT 3236 East at Henlawson, WV
d.w.davidson: Chicago & North Western - Clinton Street
d.w.davidson: Norfolk Southern - Tuscaloosa, AL
d.w.davidson: MKT - McAlester, OK
brian.m.rule241: Satellites
string_bass_dave: Centralized Traffic Control