North American interlocking towers

Towers as of December 31, 2009

A key to symbols is available.

Canada   3

Ontario   3

Name Location Railroad(s) Machine Structure Notes
Cherry Street Toronto TTR, CN, CP ETjunction of TTR and CN Kingston and Bala Subdivisions and CP Belleville Subdivision east of Union Station
John Street Toronto TTR, CN, CP ETwest throat of Toronto Union Station and junctions between CN Oakville and Weston Subdivisions and CP Galt Subdivision west of Union Station
Scott Street Toronto TTR ETeast throat of Toronto Union Station

United States   101  (40 closed)

California   6

Name Location Railroad(s) Machine Structure Notes
"I" Street Bridge Sacramento SP B
Black Point Black Point California Northern (ex-NWP) B
Brazos Brazos California Northern (ex-NWP) B
Orwood Orwood AT&SF B
Petaluma Petaluma California Northern (ex-NWP) B
Suisun Bay Bridge Martinez SP B

District of Columbia   1

Name Location Railroad(s) Machine Structure Notes
K Tower Washington Amtrak RTWashington Union Station; modernized in 1980s

Illinois   23  (11 closed)

Chicago area   17  (8 closed)

Amtrak   0  (2 closed)

Name Location Railroad(s) Machine Structure Notes
21st Street Chicago Amtrak (ex-CUS), CR (ex-PRR), IC (ex-IC and ex-GM&O) EPTcrossing and junction; formerly run by C&WI; closed February 15, 2005; razed 2006
Lake Street Chicago Amtrak (ex-CUS) EPTChicago Union Station north throat; closed ca. 2005

CN (ex-Elgin, Joliet & Eastern)   2

Name Location Railroad(s) Machine Structure Notes
Bridge Jct. Joliet CN (ex-EJ&E) Bcabin
West Chicago West Chicago CN (ex-EJ&E), UP (ex-C&NW) TUP Geneva Subdivision (West Line) crossing

CN (ex-Grand Trunk Western)   1

Name Location Railroad(s) Machine Structure Notes
Blue Island Blue Island CN (ex-GTW), CSX (ex-B&OCT), IHB RTcrossing

CSX (ex-B&OCT)   1

Name Location Railroad(s) Machine Structure Notes
South Branch Bridge Chicago CSX (ex-B&OCT), IC EBIC St. Charles Air Line bridge over south branch of Chicago River (bridge cabin)

CSX (ex-CRI&P)   1

Name Location Railroad(s) Machine Structure Notes
Bridge 407 Joliet CSX (ex-CRI&P) Bbridge cabin

Illinois Central   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Corwith Chicago AT&SF, IC/Metra Heritage (ex-GM&O) E,RTcrossing; closed November 9, 2008; razed

Indiana Harbor Belt   1

Name Location Railroad(s) Machine Structure Notes
Dolton Dolton IHB, UP (ex-C&WI, ex-C&EI, CSX (ex-B&OCT), IHB (ex-CR, nee PRR) MTtransferred to IHB from CR on March 1, 1996

Metra Electric (ex-IC)   0  (2 closed)

Name Location Railroad(s) Machine Structure Notes
67th Street Chicago Metra (ex-IC) ETSouth Chicago branch junction; closed May 18, 2009; standing
Kensington Chicago Metra (ex-IC), CSS&SB RTjunction with Blue Island branch and CSS&SB; closed December 12, 2008; standing

Metra Milwaukee District (ex-CMStP&P)   4

Name Location Railroad(s) Machine Structure Notes
A-2 (Western Ave.) Chicago Metra/Soo (ex-CMStP&P), UP (ex-C&NW) EPTcrossing with UP Geneva Subdivision (West Line)
A-5 (Pacific Jct.) Chicago Metra/Soo (ex-CMStP&P) RTjunction between Metra Milwaukee District North and West Lines and and Soo Kingsbury branch
B-17 Bensenville Metra/Soo (ex-CMStP&P) RTjunction; staffed by Soo
Rondout Rondout Metra/Soo (ex-CMStP&P), CN (ex-EJ&E) RTFox Lake branch junction, CN (ex-EJ&E) crossing; staffed by Soo/CP

Metra Rock Island District (ex-CRI&P)   4

Name Location Railroad(s) Machine Structure Notes
16th Street Chicago Metra (ex-CRI&P), IC E, RTIC (Iowa Division and St. Charles Air Line) crossing
Blue Island Blue Island Metra (ex-CRI&P) Tjunction between main and suburban lines
Gresham Chicago Metra (ex-CRI&P), CRL (ex-CRI&P) RTjunction
UD Joliet Metra (ex-CRI&P), AT&SF, SP (ex-GM&O) ETnext to Joliet Union Station

Norfolk Southern   1

Name Location Railroad(s) Machine Structure Notes
Cummings Bridge Chicago NS (ex-NKP) BCalumet River bridge, also controls Pullman Jct.; bridge cabin or tower?

Norfolk Southern (ex-CR&I)   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Brighton Park Chicago NS (ex-PRR, ex-CR&I), CSX (ex-B&OCT), IC (Metra Heritage, ex-GM&O); closed July 6, 2007 MCnon-interlocked, employees classified as switchtenders; cabin (M, w/pipeline)

Union Pacific (ex-Chicago & North Western)   2  (2 closed)

Name Location Railroad(s) Machine Structure Notes
Barrington Barrington UP (ex-C&NW) Oend of double/triple track; inside depot, part time
CY Chicago UP (ex-C&NW), Soo (ex-CMStP&P) RTjunction of UP Kenosha and Harvard subdivisions (North and Northwest Lines) and crossing with Soo Kingsbury line; also controls Mayfair interlocking on UP Northwest line and CTC on UP between Clybourn and Winnetka
Deval Des Plaines UP (ex-C&NW), WC (ex-Soo) ETcrossings of UP Harvard Subdivision (Northwest Line), C&NW freight cutoff, WC (ex-Soo); damaged in fire March 26, 2005; closed June 11, 2005
Lake Street Chicago UP (ex-C&NW) ETpassenger terminal throat

Downstate Illinois   3  (3 closed)

Central Illinois   2  (1 closed)

Name Location Railroad(s) Machine Structure Notes
BJ Tower Peoria P&PU Tdispatcher, bridge and ex-PT crossing
Pearl Pearl Gateway Western (ex-GM&O) BIllinois River bridge (bridge cabin)
Ridgely Springfield UP (ex-GM&O), C&IM (M, w/pipeline) MT

Northern Illinois (outside Chicago area)   1

Name Location Railroad(s) Machine Structure Notes
Rock Island Rock Island Iowa Interstate (ex-CRI&P) BMississippi River bridge; bridge cabin -- not verified

Southern Illinois   0  (2 closed)

Name Location Railroad(s) Machine Structure Notes
Centralia (NY) Centralia IC, BN (CB&Q), NS (Southern) ROcrossing; inside IC yard office
Mt. Vernon Mt. Vernon UP (ex-C&EI), NS, CSX (ex-L&N) Ccrossing; one-story cabin built 1975 -- to have been closed 1994, but verified as active on May, 2001

East St. Louis area   3

Name Location Railroad(s) Machine Structure Notes
HN Cabin Rose Lake CSX (ex-B&O), CSX (ex-PRR), A&S RTbuilding is a tower in spite of the term "cabin"
Lenox Mitchell UP (ex-MP, nee NYC), UP (ex-GM&O), Gateway Eastern, NS (ex-Wabash), A&S ET
Willows East St. Louis Gateway Eastern ET(ex-PRR), CSX (ex-B&O), TRRA, NS (ex-Southern)

Indiana   1  (4 closed)

Chicago area   1  (3 closed)

Name Location Railroad(s) Machine Structure Notes
Calumet East Chicago IHB, CSX (ex-B&OCT), CN (ex-EJ&E) MT
Grasselli East Chicago IHB, CN (ex-EJ&E), CSX (ex-B&OCT) MT(M, w/pipeline); closed November, 2007; moved and restored at Hoosier Valley Rail Museum, North Judson, IN
Hick Indiana Harbor NS (ex-NYC), IHB, CN (ex-EJ&E), CSX (ex-B&OCT) RTbridges and junctions employee on duty designated as a bridgetender and no longer controls signals
Indiana Harbor Canal Bridge East Chicago IHB, CN (ex-EJ&E) Copens weekdays for trains -- cabin or tower?

Outstate   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Drawbridge Michigan City Amtrak (ex-CR, nee MC) RTbridge plus CTC on Amtrak Michigan line between Porter, Indiana and Kalamazoo, Michigan; was manned by CR operators

Iowa   2

Name Location Railroad(s) Machine Structure Notes
Burlington Burlington BN (ex-CB&Q) BMississippi River bridge (bridge cabin) -- not verified
Sabula Sabula Soo (ex-CMStP&P) BMississippi River bridge and short CTC segment; bridge cabin

Kentucky   1

Name Location Railroad(s) Machine Structure Notes
Clagg Louisville L&I (ex-PRR/CR) Tbridge, south end; one shift depending on traffic, also controls Louisville & Portland Canal span

Louisiana   3

New Orleans   3

Name Location Railroad(s) Machine Structure Notes
East Bridge Jct. New Orleans IC, NOPB, NS (ex-Southern) ETconnections at east end of Huey P. Long Bridge; also controls Southport Jct.
NOPB Industrial Canal Bridge Tower New Orleans CSX (ex-L&N) Tnear drawbridges east of New Orleans -- to be remoted?
West Bridge Jct. Avondale UP (ex-T&P, ex-SP), NOPB ETconnections at west end of Huey P. Long Bridge

Maryland   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
WB West Brunswick CSX (ex-B&O) T

Massachusetts   4  (2 closed)

Name Location Railroad(s) Machine Structure Notes
Beverly Draw Beverly Amtrak (MBTA, ex-B&M) Ipswich line Bopen two tricks daily
Gloucester Draw Gloucester Amtrak (MBTA, ex-B&M) Gloucester branch B
Manchester Draw Manchester Amtrak (MBTA, ex-B&M) Gloucester branch Bopen one trick daily and closed during winter
Saugus Draw Saugus Amtrak (MBTA, ex-B&M) Ipswich line Bopen two tricks daily
South Bay ????? Amtrak (MBTA, ex-NYNH&H) Cconnections and junctions on former New Haven Dorchester Branch; located inside trailer
Waltham Waltham Amtrak (MBTA, ex-B&M) Tin addition to local interlocking, operates various interlockings on ex-B&M Fitchburg line between W. Cambridge and Acton

Michigan   5  (2 closed)

Detroit   4  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Conrail bridge Detroit CR (ex-MC) TRouge River bridge, also CP "YD" and CP "MILL"
Delray Detroit CSX (ex-C&O), GT, CR (ex-NYC), NS (ex-Wabash) EMT
NS Bridge Detroit NS (ex-Wabash), GT (ex-D&TSL) TRouge River, also controls GT/CR and CR/NS crossings at Victoria St. and NS/GT crossing at Allen Park
Schaefer Dearborn CR (ex-MC) MTclosed December 14, 2005; torn down the following day
Short Cut Bridge River Rouge CR, GT (ex-DT&I) T

Other   1  (1 closed)

Name Location Railroad(s) Machine Structure Notes
BO Kalamazoo NS (ex-MC) M, RT
FN Trenton CR (ex-MC), GT Tclosed ca. 2002; razed ca. 2005

Missouri   5

Kansas City   3

Name Location Railroad(s) Machine Structure Notes
Hannibal bridge ????? NS BMissouri River bridge -- not verified
Truman Bridge ????? Soo (ex-CMStP&P), UP (ex-C&NW, nee-CRI&P) drawbridge B
Ustick North Kansas City BN (ex-CB&Q), NS (ex-Wabash) RTclosed December 3, 2004; razed 2007

Other   2

Name Location Railroad(s) Machine Structure Notes
Hannibal Hannibal NS (ex-Wabash) RTMississippi River bridge and BN crossing; tower built 1992 to replace previous cabin
Louisiana Louisiana Gateway Western (ex-GM&O) BMississippi River bridge but not adjacent BN crossing (bridge cabin)

Nebraska   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Carling Lincoln BN (ex-CB&Q) Teast end BN yard, controls functions of former Hall Tower; closed (when?)

New Jersey   5

Amtrak Northeast Corridor   2

Name Location Railroad(s) Machine Structure Notes
Dock Newark Amtrak (ex-PRR) EPTalso controls Passaic River Bridge
Union Rahway Amtrak (ex-PRR) EP, RT

Conrail   2

Name Location Railroad(s) Machine Structure Notes
Hack Jersey City (?) CR (ex-PRR) EP, RTPassaic & Harsimus Line movable bridge over Hackensack River, CP Kearny, CP Stock, WA-5 Waverly
Upper Bay Newark CR (ex-PRR, LV) RBNational Docks Secondary, movable Newark Bay bridge formerly used jointly by PRR and LV

NJ Transit   1

Name Location Railroad(s) Machine Structure Notes
Hoboken Terminal Hoboken NJT (ex-EL) Treplaced earlier tower at same interlocking

New York   17

New York City area   16

Amtrak Northeast Corridor (ex-PRR)   2

Name Location Railroad(s) Machine Structure Notes
Q Tower Queens Amtrak (ex-PRR) EPTSunnyside Yard
R Tower Queens Amtrak (ex-PRR) EPTSunnyside Yard

Long Island Rail Road   14

Name Location Railroad(s) Machine Structure Notes
Babylon Babylon LIRR T
Brook Brooklyn LIRR TFlatbush Avenue
Divide Hicksville LIRR T
Dunton Jamaica LIRR Tclosed
East New York Queens LIRR Tclosed; had been open only as needed
Hall Jamaica LIRR Tclosed
Harold Long Island City LIRR T
Jay Jamaica LIRR Tclosed
Lead Island Park LIRR Tswing bridge -- tower or bridge cabin?
Nassau Mineola LIRR T
PD Patchogue LIRR Tclosed May 8, 2006; razed August 22, 2006
Queens Queens Village LIRR T
Valley Valley Stream LIRR T
Van Brooklyn LIRR TFlatbush Avenue tunnel approach, junction, Vanderbilt Avenue Yard, two tricks on weekdays only

Outstate   1

Name Location Railroad(s) Machine Structure Notes
LAB (Livingston Avenue Bridge) Albany-Rensselaer CSX (ex, CR, nee NYC) RCdrawbridge -- tower or bridge cabin?

Ohio   14  (3 closed)

Cleveland area   5

Name Location Railroad(s) Machine Structure Notes
Bridge 184.50 ????? NS (ex-NKP) BCuyahoga River
Bridge 222 ????? W&LE (ex-NKP) TCuyahoga River
Bridge 4 ????? CR (ex-NYC) TCuyahoga River
Bridge 460 ????? CSX (ex-B&O) BCuyahoga River
Drawbridge (DB) Cleveland NS (ex-NYC) TCuyahoga River

Columbus   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Scioto Columbus CSX (ex-B&O), CR (NYC) ETclosed August 2, 2002; razed in 2006

Other points   6

Name Location Railroad(s) Machine Structure Notes
Bay Bridge ????? NS (ex-NYC) TSandusky Bay bridge
CO Port Clinton NS (ex-NYC) Tdrawbridge
F Tower Fostoria CSX (ex-B&O), CSX (ex-C&O), NS (ex-NKP) 2015 RT
HN Newton Falls CSX (ex-B&O) EPTtower was part of depot structure; closed October 2009
JM Ashtabula CSX (ex-NYC) Ttower/drawbridge
RU Lorain Black River Bridge, NS (ex-NKP) B

Toledo area   3  (2 closed)

Name Location Railroad(s) Machine Structure Notes
Hallett Toledo AA-CSX (ex-TT) EMT
Lower Bridge Toledo CSX (ex-TT) BMaumee River
Stanley (SA) Toledo CSX (ex-NYC) ETclosed ????; razed December 17, 2014
Walbridge Toledo CSX (ex-C&O) Oyard office
Walbridge (WR) Toledo CSX (ex-PRR), CSX (ex-C&O) EPTclosed ????; razed December 11, 2014

Pennsylvania   11  (8 closed)

Other   4  (2 closed)

CSX, ex-B&O Cumberland-Connellsville main line   1

Name Location Railroad(s) Machine Structure Notes
VI Connellsville CSX (ex-B&O) Oex "D" (inside old yard office); closed 2008???

Norfolk Southern, ex-PRR main line   1  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Alto Altoona NS (ex-PRR) ET
C (Conemaugh) Johnstown NS (ex-PRR) EPTclosed October 27, 2003; razed

Pittsburgh area   2  (1 closed)

Name Location Railroad(s) Machine Structure Notes
East Conway East Conway Norfolk Southern (ex-PRR) T
Glenwood Glenwood CSX (ex-B&O) EPTclosed October 1, 2003
Midland Midland ??? Tpart time -- who operates?

Philadelphia area   7  (6 closed)

Amtrak Harrisburg Line   6

Name Location Railroad(s) Machine Structure Notes
Cork Lancaster Amtrak (ex-PRR) EPT
Overbrook Philadelphia Amtrak (ex-PRR) EPT
Paoli Paoli Amtrak (ex-PRR) EP, RT
Park Parkesburg Amtrak (ex-PRR) Topen only as needed
State Harrisburg Amtrak (ex-PRR), NS (ex-PRR, RDG) EP, ROinside Harrisburg depot
Thorn Thorndale Amtrak (ex-PRR) RT

Amtrak Northeast Corridor   1  (1 closed)

Name Location Railroad(s) Machine Structure Notes
North Philadelphia Philadelphia Amtrak EPTclosed ca. April 2005
Zoo Philadelphia Amtrak (ex-PRR) EPT

SEPTA -- Airport Line   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
A Philadelphia SEPTA, CR (ex-RDG) Tnew tower (block-like building) built 1984, controls Airport Line, CR access

SEPTA -- Chestnut Hill Line (ex-PRR)   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Chestnut Hill West Chestnut Hill SEPTA (ex-PRR) Oinside station, part time

SEPTA -- Main Line   0  (3 closed)

Name Location Railroad(s) Machine Structure Notes
Broad Philadelphia SEPTA (ex-PRR) ROoffice inside Suburban Station
Mark Philadelphia SEPTA OMarket Street East station, also controls Vine; new office built 1984
Wayne Jct. Philadelphia SEPTA (ex-RDG) Tclosed 2003 tower also houses Wind, controls various interlockings on SEPTA's ex-RDG trackage

Texas   1  (5 closed)

Name Location Railroad(s) Machine Structure Notes
#106 (Tower A) Dallas UP TDallas Union Terminal
#121 San Antonio SP E,RTyard; closed February 26, 2001; burned January 16, 2003, and razed shortly thereafter
#17 Rosenburg SP, AT&SF ETclosed February 10, 2004; moved and preserved as museum
#47 El Paso SP Tyard; closed ???
#97 (Causeway) Galveston AT&SF, SP, UP Ooffice
Beaumont (no number) Beaumont KCS RTNeches River bridge and adjacent junctions with SP, AT&SF

Virginia   1

Name Location Railroad(s) Machine Structure Notes
Bridge 5 Norfolk NS (ex-N&W) Tcontrols several junctions and a drawbridge (tower off end of bridge)

West Virginia   1  (3 closed)

Name Location Railroad(s) Machine Structure Notes
HO Hancock CSX (ex-B&O) MT(M, w/pipeline); closed September 16, 2007; razed
MK Rowlesburg CSX (ex-B&O) MTM&K Jct.
NA Martinsburg CSX (ex-B&O) RCcabin; closed July 19, 2003
Z West Keyser CSX (ex-B&O) MT(M, w/pipeline) closed September 2008; razed January 13, 2009

Key to symbols

Machine type symbols:
E Electric (typically GRS model machine).
EM Electro-mechanical. This type of machine has a mechanical frame with separate electrical levers that are either electrically or mechanically interlocked with mechanical frame.
EP Electro-pneumatic (typically US&S model machine).
M Mechanical frame (old “armstrong” or “strong-arm” levers). The presence of pipeline-operated switches, derails, or signals is indicated when known.
R All-relay machine. Includes CTC- and “NX” or “UR”-style panels, as well as other more modern variants that lack mechanical locking.
Structure type symbols:
B Movable bridge cabin, on or next to bridge.
C Cabin (one-story free-standing building).
O Office (e. g., yard office or depot building).
T Tower (building with two or more stories)