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 90 (30 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 22 (7 closed)

Chicago area 16 (4 closed)

Amtrak 0 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Lake Street	Chicago	Amtrak (ex-CUS)	EP	T	Chicago 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)		B	cabin
West Chicago	West Chicago	CN (ex-EJ&E), UP (ex-C&NW)		T	UP 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	R	T	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

Illinois Central 0 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Corwith	Chicago	AT&SF, IC/Metra Heritage (ex-GM&O)	E,R	T	crossing; 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)	M	T	transferred to IHB from CR on March 1, 1996

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)	EP	T	crossing with UP Geneva Subdivision (West Line)
A-5 (Pacific Jct.)	Chicago	Metra/Soo (ex-CMStP&P)	R	T	junction between Metra Milwaukee District North and West Lines and and Soo Kingsbury branch
B-17	Bensenville	Metra/Soo (ex-CMStP&P)	R	T	junction; staffed by Soo
Rondout	Rondout	Metra/Soo (ex-CMStP&P), CN (ex-EJ&E)	R	T	Fox Lake branch junction, CN (ex-EJ&E) crossing; staffed by Soo/CP

Metra Rock Island District (ex-CRI&P) 3 (1 closed)

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
Gresham	Chicago	Metra (ex-CRI&P), CRL (ex-CRI&P)	R	T	junction; closed January 31, 2010
UD	Joliet	Metra (ex-CRI&P), AT&SF, SP (ex-GM&O)	E	T	next to Joliet Union Station

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 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
CY	Chicago	UP (ex-C&NW), Soo (ex-CMStP&P)	R	T	junction 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)	E	T	crossings of UP Harvard Subdivision (Northwest Line), C&NW freight cutoff, WC (ex-Soo); damaged in fire March 26, 2005; closed June 11, 2005; razed November 26, 2012
Lake Street	Chicago	UP (ex-C&NW)	E	T	passenger terminal throat

Downstate Illinois 3 (3 closed)

Central Illinois 2 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
BJ Tower	Peoria	P&PU		T	dispatcher, bridge and ex-PT crossing
Pearl	Pearl	Gateway Western (ex-GM&O)		B	Illinois River bridge (bridge cabin)
Ridgely	Springfield	UP (ex-GM&O), C&IM (M, w/pipeline)	M	T	Last location in North America where switch and lock was operated using mechanical pipeline; closed June 29, 2010; razed August 8, 2011

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

Southern Illinois 0 (2 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Centralia (NY)	Centralia	IC, BN (CB&Q), NS (Southern)	R	O	crossing; inside IC yard office
Mt. Vernon	Mt. Vernon	UP (ex-C&EI), NS, CSX (ex-L&N)		C	crossing; 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	R	T	building 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	E	T
Willows	East St. Louis	Gateway Eastern	E	T	(ex-PRR), CSX (ex-B&O), TRRA, NS (ex-Southern)

Indiana 1 (2 closed)

Chicago area 1 (2 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Calumet	East Chicago	IHB, CSX (ex-B&OCT), CN (ex-EJ&E)	M	T
Hick	Indiana Harbor	NS (ex-NYC), IHB, CN (ex-EJ&E), CSX (ex-B&OCT)	R	T	bridges and junctions; remoted to dispatcher, July 11, 2010, employee on duty designated as a bridgetender and no longer controls signals
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 3

New Orleans 3

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 controls Southport Jct.
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

Maryland 0 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
WB	West Brunswick	CSX (ex-B&O)		T	closed December 9, 2011; standing

Massachusetts 4 (2 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	?????	Amtrak (MBTA, ex-NYNH&H)	C	connections and junctions on former New Haven Dorchester Branch; located inside trailer
Waltham	Waltham	Amtrak (MBTA, ex-B&M)	T	in addition to local interlocking, operates various interlockings on ex-B&M Fitchburg line between W. Cambridge and Acton

Michigan 5

Detroit 4

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
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

Other 1

Name	Location	Railroad(s)	Machine	Structure	Notes
BO	Kalamazoo	NS (ex-MC)	M, R	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)

Nebraska 0 (1 closed)

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

New Jersey 4 (1 closed)

Amtrak Northeast Corridor 1 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Dock	Newark	Amtrak (ex-PRR)	EP	T	also controls Passaic River Bridge
Union	Rahway	Amtrak (ex-PRR)	EP, R	T	closed September 26, 2010

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 13 (3 closed)

New York City area 12 (3 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 10 (3 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Babylon	Babylon	LIRR		T
Brook	Brooklyn	LIRR		T	Flatbush Avenue
Divide	Hicksville	LIRR		T
Dunton	Jamaica	LIRR	EP	T	closed November 2010?
East New York	Queens	LIRR		T	closed; had been open only as needed
Hall	Jamaica	LIRR	EP	T	closed November 2010
Harold	Long Island City	LIRR		T
Jay	Jamaica	LIRR	EP	T	closed November 2010
Lead	Island Park	LIRR		T	swing bridge -- tower or bridge cabin?
Nassau	Mineola	LIRR		T
Queens	Queens Village	LIRR		T
Valley	Valley Stream	LIRR		T
Van	Brooklyn	LIRR		T	Flatbush 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)	R	C	drawbridge -- tower or bridge cabin?

Ohio 13 (3 closed)

Cleveland area 5

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
Drawbridge (DB)	Cleveland	NS (ex-NYC)	T	Cuyahoga River

Other points 5 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Bay Bridge	?????	NS (ex-NYC)		T	Sandusky Bay bridge
CO	Port Clinton	NS (ex-NYC)		T	drawbridge
F Tower	Fostoria	CSX (ex-B&O), CSX (ex-C&O), NS (ex-NKP) 2015	R	T
HN	Newton Falls	CSX (ex-B&O)	EP	T	tower was part of depot structure; closed October 2009; razed shortly after being damaged in derailment March 28, 2011
JM	Ashtabula	CSX (ex-NYC)		T	tower/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)	EM	T
Lower Bridge	Toledo	CSX (ex-TT)		B	Maumee River
Stanley (SA)	Toledo	CSX (ex-NYC)	E	T	closed ????; razed December 17, 2014
Walbridge	Toledo	CSX (ex-C&O)		O	yard office
Walbridge (WR)	Toledo	CSX (ex-PRR), CSX (ex-C&O)	EP	T	closed ????; razed December 11, 2014

Pennsylvania 9 (4 closed)

Other 2 (3 closed)

CSX, ex-B&O Cumberland-Connellsville main line 0 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
VI	Connellsville	CSX (ex-B&O)		O	ex "D" (inside old yard office); closed ca. 2010

Norfolk Southern, ex-PRR main line 0 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
Alto	Altoona	NS (ex-PRR)	E	T	closed June 16, 2012; standing

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)	EP	T	closed October 1, 2003
Midland	Midland	???		T	part time -- who operates?

Philadelphia area 7 (1 closed)

Amtrak Harrisburg Line 6

Name	Location	Railroad(s)	Machine	Structure	Notes
Cork	Lancaster	Amtrak (ex-PRR)	EP	T
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
State	Harrisburg	Amtrak (ex-PRR), NS (ex-PRR, RDG)	EP, R	O	inside Harrisburg depot
Thorn	Thorndale	Amtrak (ex-PRR)	R	T

Amtrak Northeast Corridor 1

Name	Location	Railroad(s)	Machine	Structure	Notes
Zoo	Philadelphia	Amtrak (ex-PRR)	EP	T

SEPTA -- Main Line 0 (1 closed)

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

Texas 1 (5 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
#106 (Tower A)	Dallas	UP		T	Dallas Union Terminal
#121	San Antonio	SP	E,R	T	yard; closed February 26, 2001; burned January 16, 2003, and razed shortly thereafter
#17	Rosenburg	SP, AT&SF	E	T	closed February 10, 2004; moved and preserved as museum
#47	El Paso	SP		T	yard; closed November 1997
#97 (Causeway)	Galveston	AT&SF, SP, UP		O	office
Beaumont (no number)	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 off end of bridge)

West Virginia 0 (1 closed)

Name	Location	Railroad(s)	Machine	Structure	Notes
MK	Rowlesburg	CSX (ex-B&O)	M	T	M&K Jct.; closed December 8, 2010; razed

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)