North American interlocking towers

NOTE:

This list and the information contained therein may be freely reproduced or used in printed or electronic form for non-commercial purposes, provided the source is acknowledged and provided that such publication also refers readers to the original list on this site.

A key to symbols is available.

Canada 3

Ontario 3

Name	Location	Railroad(s)	Machine	Structure	Notes
Cherry Street	Toronto	TTR, CN, CP	E	T	junction of TTR and CN Kingston and Bala Subdivisions and CP Belleville Subdivision east of Union Station
John Street	Toronto	TTR, CN, CP	E	T	west 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	E	T	east throat of Toronto Union Station

United States 60 (16 closed)

California 6

Name	Location	Railroad(s)	Structure
"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	R	T	Washington 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)		B	cabin
West Chicago	West Chicago	CN (ex-EJ&E), UP (ex-C&NW)		T	UP 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	E	B	IC 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)		B	bridge 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)	M	T	transferred 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)	EP	T	crossing with UP Geneva Subdivision (West Line)
B-17	Bensenville	Metra/CP (ex-Soo, nee CMStP&P)	R	T	junction; 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, R	T	IC (Iowa Division and St. Charles Air Line) crossing
Blue Island	Blue Island	Metra (ex-CRI&P)		T	junction between main and suburban lines

Norfolk Southern 1

Name	Location	Railroad(s)	Machine	Structure	Notes
Cummings Bridge	Chicago	NS (ex-NKP)		B	Calumet 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)	R	T	junction 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)	E	T	passenger terminal throat

Downstate Illinois 2

Central Illinois 1

Name	Location	Railroad(s)	Machine	Structure	Notes
Pearl	Pearl	Gateway Western (ex-GM&O)		B	Illinois 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)		B	Mississippi 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	E	T	closed October 29, 2018; was last active tower in St. Louis area; razed May 17, 2021
Willows	East St. Louis	Gateway Eastern	E	T	(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)		C	opens weekdays for trains -- cabin or tower?

Iowa 2

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

Kentucky 1

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

Louisiana 1 (2 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
East Bridge Jct.	New Orleans	IC, NOPB, NS (ex-Southern)	E	T	connections at east end of Huey P. Long Bridge; also controlled Southport Jct.; closed June 2019
NOPB Industrial Canal Bridge Tower	New Orleans	CSX (ex-L&N)		T	near drawbridges east of New Orleans -- to be remoted?
West Bridge Jct.	Avondale	UP (ex-T&P, ex-SP), NOPB	E	T	connections at west end of Huey P. Long Bridge; closed August 29, 2017

Massachusetts 4 (1 closed)

Name	Location	Railroad(s)	Structure	Notes
Beverly Draw	Beverly	Amtrak (MBTA, ex-B&M) Ipswich line	B	open two tricks daily
Gloucester Draw	Gloucester	Amtrak (MBTA, ex-B&M) Gloucester branch	B
Manchester Draw	Manchester	Amtrak (MBTA, ex-B&M) Gloucester branch	B	open one trick daily and closed during winter
Saugus Draw	Saugus	Amtrak (MBTA, ex-B&M) Ipswich line	B	open two tricks daily
South Bay	Saugus	Amtrak (MBTA, ex-NYNH&H)	C	connections and junctions on former New Haven Dorchester Branch; located inside trailer

Michigan 3 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Conrail bridge	Detroit	CR (ex-MC)		T	Rouge River bridge, also CP "YD" and CP "MILL"
Delray	Detroit	CSX (ex-C&O), GT, CR (ex-NYC), NS (ex-Wabash)	EM	T	Closed November 16, 2020
NS Bridge	Detroit	NS (ex-Wabash), GT (ex-D&TSL)		T	Rouge 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		B	Missouri 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)	R	T	Mississippi River bridge and BN crossing; tower built 1992 to replace previous cabin
Louisiana	Louisiana	Gateway Western (ex-GM&O)		B	Mississippi 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)	EP	T	also controlled Passaic River Bridge; closed November 13, 2017

Conrail 2

Name	Location	Railroad(s)	Machine	Structure	Notes
Hack	Jersey City (?)	CR (ex-PRR)	EP, R	T	Passaic & Harsimus Line movable bridge over Hackensack River, CP Kearny, CP Stock, WA-5 Waverly
Upper Bay	Newark	CR (ex-PRR, LV)	R	B	National 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)		T	replaced earlier tower at same interlocking

New York 6 (5 closed)

New York City area 6 (5 closed)

Amtrak Northeast Corridor (ex-PRR) 2

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

Long Island Rail Road 4 (5 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Babylon	Babylon	LIRR		T
Brook	Brooklyn	LIRR		T	Flatbush Avenue
Divide	Hicksville	LIRR		T
East New York	Queens	LIRR		T	closed; had been open only as needed
Lead	Island Park	LIRR		T	swing bridge -- tower or bridge cabin?
Nassau	Mineola	LIRR	R	T	closed July 11, 2020 as a result of triple-tracking
Queens	Queens Village	LIRR		T	Closed January 11, 2020
Valley	Valley Stream	LIRR		T
Van	Brooklyn	LIRR		T	Flatbush Avenue tunnel approach, junction, Vanderbilt Avenue Yard, two tricks on weekdays only

Ohio 6 (1 closed)

Cleveland area 6

Name	Location	Railroad(s)	Structure	Notes
Bridge 184.50	?????	NS (ex-NKP)	B	Cuyahoga River
Bridge 222	?????	W&LE (ex-NKP)	T	Cuyahoga River
Bridge 4	?????	CR (ex-NYC)	T	Cuyahoga River
Bridge 460	?????	CSX (ex-B&O)	B	Cuyahoga River
JM	Ashtabula	CSX (ex-NYC)	T	tower/drawbridge
RU	Lorain	Black River Bridge, NS (ex-NKP)	B

Toledo area 0 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Hallett	Toledo	AA-CSX (ex-TT)	EM	T	closed April 13, 2019; tower housed AA dispatcher

Pennsylvania 7 (1 closed)

Philadelphia area 5 (1 closed)

Amtrak 5

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

SEPTA 0 (1 closed)

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

Pittsburgh area 2

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

Texas 1 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
#97 (Causeway)	Galveston	AT&SF, SP, UP	R	O	controls lift bridge
KCS Tower	Beaumont	KCS	R	T	Neches 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)		T	controls several junctions and a drawbridge (tower at end of bridge)

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)