North American interlocking towers

Current towers

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   70  (11 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   13  (3 closed)

Chicago area   11  (1 closed)

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

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

Indiana Harbor Belt   0  (1 closed)

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; closed February 23, 2017; razed August 2017

Metra Milwaukee District (ex-CMStP&P)   2

Name Location Railroad(s) Machine Structure Notes
A-2 (Western Ave.) Chicago Metra/CP (ex-Soo, nee CMStP&P), UP (ex-C&NW) EPTcrossing with UP Geneva Subdivision (West Line)
B-17 Bensenville Metra/CP (ex-Soo, nee CMStP&P) RTjunction; staffed by CP

Metra Rock Island District (ex-CRI&P)   2

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

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?

Union Pacific (ex-Chicago & North Western)   2

Name Location Railroad(s) Machine Structure Notes
CY Chicago UP (ex-C&NW), CP (ex-Soo, nee CMStP&P) RTjunction of UP Kenosha and Harvard subdivisions (North and Northwest Lines) and crossing with ex-CMStP&P Kingsbury line until that was severed; also controls Mayfair interlocking on UP Northwest line and CTC on UP between Clybourn and Winnetka
Lake Street Chicago UP (ex-C&NW) ETpassenger terminal throat

Downstate Illinois   2

Central Illinois   1

Name Location Railroad(s) Machine Structure Notes
Pearl Pearl Gateway Western (ex-GM&O) BIllinois River bridge (bridge cabin)

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

East St. Louis area   0  (2 closed)

Name Location Railroad(s) Machine Structure Notes
Lenox Mitchell UP (ex-MP, nee NYC), UP (ex-GM&O), Gateway Eastern, NS (ex-Wabash), A&S ETclosed October 29, 2018; was last active tower in St. Louis area
Willows East St. Louis Gateway Eastern ET(ex-PRR), CSX (ex-B&O), TRRA, NS (ex-Southern); closed September 10, 2018

Indiana   1

Name Location Railroad(s) Machine Structure Notes
Indiana Harbor Canal Bridge East Chicago IHB, CN (ex-EJ&E) Copens weekdays for trains -- cabin or tower?

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   2  (1 closed)

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; closed August 29, 2017

Massachusetts   4  (1 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 Saugus Amtrak (MBTA, ex-NYNH&H) Cconnections and junctions on former New Haven Dorchester Branch; located inside trailer

Michigan   4

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
Short Cut Bridge River Rouge CR, GT (ex-DT&I) T

Missouri   4

Kansas City   2

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

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)

New Jersey   3  (1 closed)

Amtrak Northeast Corridor   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Dock Newark Amtrak (ex-PRR) EPTalso controlled Passaic River Bridge; closed November 13, 2017

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   8  (3 closed)

New York City area   8  (3 closed)

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   6  (3 closed)

Name Location Railroad(s) Machine Structure Notes
Babylon Babylon LIRR T
Brook Brooklyn LIRR TFlatbush Avenue
Divide Hicksville LIRR T
East New York Queens LIRR Tclosed; had been open only as needed
Lead Island Park LIRR Tswing bridge -- tower or bridge cabin?
Nassau Mineola LIRR T
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

Ohio   12

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

Other points   4

Name Location Railroad(s) Machine Structure Notes
Bay Bridge ????? NS (ex-NYC) TSandusky Bay bridge
CO Port Clinton NS (ex-NYC) Tdrawbridge
JM Ashtabula CSX (ex-NYC) Ttower/drawbridge
RU Lorain Black River Bridge, NS (ex-NKP) B

Toledo area   3

Name Location Railroad(s) Machine Structure Notes
Hallett Toledo AA-CSX (ex-TT) EMT
Lower Bridge Toledo CSX (ex-TT) BMaumee River
Walbridge Toledo CSX (ex-C&O) Oyard office

Pennsylvania   7  (1 closed)

Philadelphia area   5  (1 closed)

Amtrak   5

Name Location Railroad(s) Machine Structure Notes
Overbrook Philadelphia Amtrak (ex-PRR) EPT
Paoli Paoli Amtrak (ex-PRR) EP, RT
Park Parkesburg Amtrak (ex-PRR) Topen only as needed
Thorn Thorndale Amtrak (ex-PRR) RT
Zoo Philadelphia Amtrak (ex-PRR) EPT

SEPTA   0  (1 closed)

Name Location Railroad(s) Machine Structure Notes
Broad Philadelphia SEPTA (ex-PRR) ROoffice inside Suburban Station

Pittsburgh area   2

Name Location Railroad(s) Machine Structure Notes
East Conway East Conway Norfolk Southern (ex-PRR) T
Midland Midland ??? Tpart time -- who operates?

Texas   1  (1 closed)

Name Location Railroad(s) Machine Structure Notes
#97 (Causeway) Galveston AT&SF, SP, UP ROcontrols lift bridge
KCS Tower 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 at end of bridge)

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)