Railway Signaling | D

NOTE:

Although all of these digitized articles are 60 or more years old, and likely have minimal commercial value today, the reader should bear in mind that material dated after 1923 remains under copyright by Simmons-Boardman Publishing.

These articles and the information contained therein may be freely reproduced or used in printed or electronic form for non-commercial or educational purposes, provided the copyright holder and original author (if known) are acknowledged, and provided that such publication also refers readers to the original document on this site.

Simply making interesting material available to those who share my interest in the railway signal systems of the past has been my sole objective in this long project.

Learn more about this collection.

"D" Tower, Grafton, WV 1

1965	B&O would have used radio orders 565.5 KB

Daggett, CA 2

1944	Track Circuits on Passing Tracks in CTC Territory 941.8 KB
1943	Union Pacific Installs CTC on 175 Miles of Single Track 13.2 MB

Dakota Jct., NE 1

1924	Low-Voltage Interlocking on C&NW 1.6 MB

Dale, WY 1

1955	CTC and cab signaling on Union Pacific 789.5 KB

Dalies, AZ 1

1961	Santa Fe Signals New Main Line 913.2 KB

Dalies, OK 1

1947	Railroads Request Relief from the ICC Signal Order 365.7 KB

Dallas Union Terminal 2

1962	News briefs. 1962-05 826.8 KB
1936	Reconstruction of Interlocking at the Dallas Union Terminal 14.8 MB

Dallas, TX 5

1935	Centralized Traffic Control on the Texas & Pacific 5.1 MB
1935	Collision on the T&P 2.0 MB
1936	Reconstruction of Interlocking at the Dallas Union Terminal 14.8 MB
1955	Santa Fe installs CTC on single track 610.2 KB
1949	Signaling Adapted to Traffic On the Rock Island 5.2 MB

Dalton, GA 1

1955	What CTC did for the Dixie Line 889.8 KB

Dalton, PA 2

1961	News briefs. 1961-07 648.9 KB
1962	News briefs. 1962-07 494.2 KB

Danville Jct., IL 1

1947	All-Relay Plant on the C&EI at Danville, Ill 915.6 KB

Danville, IL 12

1947	All-Relay Plant on the C&EI at Danville, Ill 915.6 KB
1911	Automatic Signals on Vermillion River Bridge 986.3 KB
1931	Centralized Traffic Control Installed on Wabash 5.6 MB
1948	CTC Keeps ‘em Rollin’ on C&EI 2.1 MB
1925	Division Train Control Installation on C&EI Approved by ICC 2.9 MB
1960	News briefs. 1960-10 1.8 MB
1960	News briefs. 1960-11 875.5 KB
1961	News briefs. 1961-03 1.0 MB
1965	News briefs. 1965-07 788.3 KB
1930	Remotely Controlled Signals Replace Manual Block Station on New York Central 1.2 MB
1911	Signaling on the Illinois Traction System 1.5 MB
1926	Train Control Progress in 1925 3.1 MB

Darby Creek, PA 1

1922	News of the Month. 1922-02 323.2 KB

Davenport, IA 1

1916	Government Drawbridge Signaling 670.2 KB

Davenport, Rock Island & North Western 1

1960	Fourteen RRs adopt new operating code 945.4 KB

Davenport, Rock Island & Northwestern 1

1941	Protection at 38 Street Crossings In and Near Rock Island, Ill 3.1 MB

Davis equation 2

1960	Computer analyzes train operation 1.2 MB
1959	Computer simulates train operation 524.0 KB

Davis, DE 1

1936	Remote Control on the Pennsylvania 14.5 MB

Davis, IL 2

1948	CTC Big Help to GM&O 1.7 MB
1915	Electric Interlocking at Davis, Illinois 241.3 KB

Davis, IN 1

1960	News briefs. 1960-03 1.9 MB

Davis, Indianapolis, IN 1

1961	News briefs. 1961-07 648.9 KB

Dayton Ave., Los Angeles, CA 1

1934	An Electric Interlocking on the Southern Pacific 1.8 MB

Dayton Union 3

1951	"Central" Increases Safety at Highway Crossings in Dayton 1.0 MB
1933	Signaling Construction During 1932 632.3 KB
1933	Simplified Interlocking Installed at the Dayton Terminal 700.6 KB

Dayton Union Terminal 1

1933	New Interlockers – Reversion to Single Track 418.4 KB

Dayton, OH 6

1951	"Central" Increases Safety at Highway Crossings in Dayton 1.0 MB
1947	Choice of Interlocking Control Machines 266.5 KB
1960	News briefs. 1960-09 756.9 KB
1929	Pennsylvania Installs APB Signaling on 86 Miles 3.7 MB
1955	Pennsylvania installs wayside equipment for cab signaling 745.7 KB
1933	Simplified Interlocking Installed at the Dayton Terminal 700.6 KB

Dayton, TX 1

1935	Switch-Stand Selector 1.9 MB

DB Tower, WV 1

1943	Centralized Traffic Control Installed on the Virginian 7.0 MB

DC coded track circuits 1

1940	11,000-Ft. Coded Track Circuits 13.6 MB

DC coding units 1

1940	Plug Couplers for Relays and Signals 1.3 MB

DC pulse code 1

1962	Remote Control Interlocking Has Time Division Multiplex System 846.3 KB

DC relay 1

1916	The New Ziegler Relay 396.2 KB

DC track circuits 1

1935	DC Track Circuits 963.2 KB

De Beque, CO 1

1955	One CTC Machine Replaces Three 451.9 KB

De Coursey Yard, Latonia, KY 1

1963	News briefs. 1963-03 790.6 KB

De Coursey, KY 3

1960	News briefs. 1960-07 845.4 KB
1962	News briefs. 1962-04 1.2 MB
1965	News briefs. 1965-02 1.9 MB

De Graff, OH 1

1932	Big Four Uses Centralized Control For Remote Interlocking 1.8 MB

De Kalb, IL 4

1958	Crossing protection program saves 59% 553.4 KB
1950	Longest Continuous Double-Track CTC Is on North Western 5.1 MB
1935	Traffic Type Signals for Protection of Highway-Railroad Crossings 2.5 MB
1927	Unique Highway Crossing Signals Solve Traffic Problem 1.4 MB

De Queen, AR 1

1955	CTC moves trains on grades 762.8 KB

De Quincy, LA 2

1963	News briefs. 1963-08 1.2 MB
1963	News briefs. 1963-11 1.4 MB

dead sections 1

1958	What's the answer? Long dead sections 571.9 KB

Deal, VA 1

1962	News briefs. 1962-10 461.7 KB

Dean, WA 1

1922	News of the Month. 1922-06 516.2 KB

Dearborn, MI 1

1946	DT&I Tests Radio 4.3 MB

Decatur, AR 1

1962	News briefs. 1962-02 1.4 MB

Decatur, IL 5

1945	Manual Block-Remote Control Developed On the Wabash 5.7 MB
1959	News briefs. 1959-05 506.5 KB
1937	Signal Construction on the Wabash 12.2 MB
1930	Wabash Tests Automatic Train Control with Cab-Lights 3.6 MB
1954	Wabash Yard Moves Expedited 1.2 MB

decoder units 1

1940	Coded Track Control 2.5 MB

Deen, CO 1

1929	D&RGW Expedites Trains With Centralized Control 2.1 MB

Deepwater, WV 1

1925	Position Light Take Siding Signal in Combination With Semaphore Installed on C&O 675.6 KB

Deer Lodge, MT 1

1917	Light Signals On CM&StP 781.9 KB

Deering, IL 1

1917	New C&NW Bascule Bridge Interlocking 761.1 KB

Delair, NJ 1

1965	News briefs. 1965-01 2.0 MB

Delano, MN 3

1957	GN CTC's 175 miles of mainline 635.9 KB
1960	News briefs. 1960-09 756.9 KB
1922	News of the Month. 1922-03 314.9 KB

Delano, VA 1

1950	Train Movements by Signal Indication On the Clinchfield Route 12.0 MB

Delavan, IL 1

1929	The Chicago & Alton Installs Mechanical Plant 1.3 MB

Delaware & Hudson 42

1925	Approach Locking Circuit That Is Dependent Upon Signal Position 648.1 KB
1947	Choice of Interlocking Control Machines 266.5 KB
1928	Circuit Polarity at Relay Contacts 526.2 KB
1955	CTC reduces operating expenses 431.8 KB
1932	CTC Studies 977.5 KB
1959	D&H upgrades crossing protection 626.4 KB
1960	How CTC affects D&H M/W work: Cuts costs 372.6 KB
1947	How Low Is a Dwarf? 438.7 KB
1922	ICC Proposes to Order Train Control on 49 Roads 376.4 KB
1958	Kink: Automatic control for waiting room 195.6 KB
1938	Light Signals as Train Order Signals 731.0 KB
1927	Multiplicity of Circuits for Operating Call-on Arms 1.5 MB
1955	News briefs. 1955-08 830.4 KB
1959	News briefs. 1959-05 506.5 KB
1960	News briefs. 1960-01 1.1 MB
1960	News briefs. 1960-02 995.4 KB
1960	News briefs. 1960-03 1.9 MB
1960	News briefs. 1960-06 1.2 MB
1961	News briefs. 1961-05 1.1 MB
1962	News briefs. 1962-02 1.4 MB
1962	News briefs. 1962-03 1.1 MB
1962	News briefs. 1962-06 989.1 KB
1963	News briefs. 1963-11 1.4 MB
1964	News briefs. 1964-02 992.4 KB
1965	News briefs. 1965-01 2.0 MB
1966	News briefs. 1966-01 1.4 MB
1922	News of the Month. 1922-06 516.2 KB
1922	News of the Month. 1922-09 562.2 KB
1931	Protecting CTC Switches 2.9 MB
1927	Several Effective Trap Circuit Schemes 1.4 MB
1927	Should Motor Car Operators Watch Signals More Carefully 1.2 MB
1960	Signal construction steady in 1959 385.2 KB
1933	Signal or Rule? 1.1 MB
1959	Signaling moderate during '58 528.6 KB
1961	Survey Tells How Railroads Use Hotbox Detectors 1.8 MB
1956	Switch Machines for CTC 2.0 MB
1938	The Outlook for Signaling 1.3 MB
1925	The Train Control Situation 853.0 KB
1926	Train Control Progress in 1925 3.1 MB
1915	Victoria Jubilee Bridge Protection 570.0 KB
1937	What is in Store for the Signal Field? 1.8 MB
1922	Work in Signal Field Shows Gain Over 1920 784.5 KB

Delaware River 1

1937	Delaware River Bridge Signaling 13.9 MB

Delaware Water Gap, PA 1

1958	News briefs. 1958-01 1.8 MB

Delaware, Lackawanna & Western 38

1908	A New 10,000 Line Telephone Exchange for Paris, France 2.2 MB
1924	Automatic Interlocker for a Crossing 3.4 MB
1922	Automatic Train Control in Use On American Railroads 353.7 KB
1951	Automatic-Manual Control for Gates at Five Crossings 418.2 KB
1935	Call-on Signal Involved In Accident 1.1 MB
1928	Continued Activity and Development in Signaling 1.1 MB
1926	Directing Trains By Signals 1.9 MB
1958	DL&W-Erie joint operation is ready to go 643.6 KB
1928	Emergency Release Circuits 2.4 MB
1959	Erie consolidates interlockings 440.6 KB
1936	Flood Damage to Signaling 5.0 MB
1927	How Many Signal Aspects and Indications? 2.4 MB
1922	ICC Proposes to Order Train Control on 49 Roads 376.4 KB
1936	Importance of Warning Whistle 6.8 MB
1936	Instructions for Crossing Protection in New York 1.8 MB
1937	J. C. Mock Retires 1.4 MB
1953	Lackawanna First to Install New Multiplex High Speed Code 4.6 MB
1957	Lehigh Valley combines interlockings 404.0 KB
1955	Much is new in signaling for 1955 826.7 KB
1935	Multiple Aspect Signaling 3.3 MB
1925	Multiple Track Operation by Signal Indication 2.7 MB
1922	New Interlocking on the CRR of NJ 734.1 KB
1958	News briefs. 1958-01 1.8 MB
1960	News briefs. 1960-04 896.6 KB
1922	News of the Month. 1922-07 346.9 KB
1931	Preparation of Signal Circuit Plans 2.0 MB
1921	Proposed Modification of Stop-and-Proceed Rule 1.4 MB
1922	Railroads Argue Against Automatic Stops at ICC Hearing 436.8 KB
1936	Railroads Clean Up After Flood Waters 33.3 MB
1937	Shunt Sensitivity and Broken Rail Protection 4.3 MB
1930	Signal Aspects for a Four Block System 2.8 MB
1960	Signaling enters automation 630.7 KB
1922	Signaling Meadows Line of DL&W 7.9 MB
1936	The Delaware, Lackawanna & Western's Approach-Lighting System for Semaphore Signals 3.4 MB
1931	The Signaling of the Lackawanna Electrified Territory 5.9 MB
1926	Train Control Progress in 1925 3.1 MB
1909	Train staff on DL&W 1.1 MB
1923	Train-Order Signals at Interlockers 3.6 MB

Delaware, Lackawanna & WEstern 1

1960	Signal construction steady in 1959 385.2 KB

Delmar, IA 2

1928	Automatic Interlockers Are Profitable Investments 3.3 MB
1951	Single Track with CTC Replaces Double Track on Milwaukee 586.0 KB

Delphi, IN 1

1958	News briefs. 1958-01 1.8 MB

Delray, Detroit, MI 1

1955	Crossing protection for 16 streets 371.1 KB

Delray, MI 3

1926	DT&I Interlocking Machine Nickel-Plated When Rebuilt 602.1 KB
1946	DT&I Tests Radio 4.3 MB
1946	War-Time Replacement of Interlocking on Pere Marquette 3.4 MB

Delson, Quebec 1

1935	Mechanical Plant Replaced by Electric Interlocking 7.2 MB

Delta, MO 1

1941	Signaling on 47 Miles of St. Louis Southwestern 12.6 MB

Demopolis, AL 1

1962	News briefs. 1962-02 1.4 MB

Den Bosch 1

1951	New Interlocking in Holland 1.0 MB

Denison, IA 1

1965	News briefs. 1965-08 749.4 KB

Denison, TX 4

1949	New Automatic Block on the Katy 4.7 MB
1961	News briefs. 1961-10 1.0 MB
1922	News of the Month. 1922-10 368.4 KB
1922	News of the Month. 1922-12 388.1 KB

Denver & Rio Grande Western 35

1949	An Unusual Automatic Plant 4.5 MB
1950	Automatic Block Increases Safety on Paired Trackage 4.6 MB
1964	Automatic identity systems proposed 736.1 KB
1927	Control of Stop Indication in Approach-Lighted Territory 972.5 KB
1950	CTC Extended on the Rio Grande 4.4 MB
1943	CTC on 107 Miles of Single-Track on the Rio Grande 9.7 MB
1937	CTC On the Denver & Rio Grande Western 8.0 MB
1932	D&RGW Completes the Signaling of Its Main Line 2.6 MB
1929	D&RGW Expedites Trains With Centralized Control 2.1 MB
1933	Economics of Modern Signaling 2.1 MB
1954	Electric Interlocking on the Rio Grande 3.4 MB
1930	Letter to the Editor- APB Signal Indications 1.0 MB
1960	News briefs. 1960-10 1.8 MB
1961	News briefs. 1961-04 1.5 MB
1961	News briefs. 1961-10 1.0 MB
1965	News briefs. 1965-05 1.4 MB
1965	News briefs. 1965-06 1.2 MB
1922	News of the Month. 1922-11 361.5 KB
1955	One CTC Machine Replaces Three 451.9 KB
1961	Overlay Circuit Reduces Joints 306.6 KB
1944	Remote Control Interlocking on the D&RGW 4.3 MB
1944	Rio Grande has Longest CTC 9.2 MB
1958	RS&C 50th anniversary: Signaling ... manual to automatic 2.0 MB
1930	Should Signal Clear? 1.2 MB
1929	Signal Aspects at End of Double Track 514.3 KB
1933	Signal or Rule? 1.1 MB
1944	Signals Direct Trains at Junction On the Denver & Rio Grande Western and the Denver & Salt Lake 2.8 MB
1961	Survey Tells How Railroads Use Hotbox Detectors 1.8 MB
1947	Territories Involved in the ICC Signaling Order 388.2 KB
1930	Time-Table Schedules and Signal Indications 1.1 MB
1932	Track Capacity 2.7 MB
1937	What is in Store for the Signal Field? 1.8 MB
1959	What's the answer? Repeater signals 691.6 KB
1958	What's the answer? Snow on signals 711.5 KB
1929	Where Should Grade Signals Be Installed? 1.2 MB

Denver & Salt Lake 6

1941	Automatic Signaling and Tunnel Protection On the Denver & Salt Lake 6.7 MB
1950	CTC Extended on the Rio Grande 4.4 MB
1946	CTC on 128 Miles of Denver & Salt Lake 10.1 MB
1922	News of the Month. 1922-06 516.2 KB
1941	Non-Stop Permissive Signals 1.4 MB
1944	Signals Direct Trains at Junction On the Denver & Rio Grande Western and the Denver & Salt Lake 2.8 MB

Denver Union Terminal 1

1959	Signaling: 1960 225.2 KB

Denver, CO 7

1941	Automatic Signaling and Tunnel Protection On the Denver & Salt Lake 6.7 MB
1928	Burlington Completes Automatic Signals Chicago to Denver 5.1 MB
1950	CTC Extended on the Rio Grande 4.4 MB
1946	CTC on 128 Miles of Denver & Salt Lake 10.1 MB
1947	ICC Holds Signal Hearing 507.5 KB
1947	Railroads Request Relief from the ICC Signal Order 365.7 KB
1935	Safety of High Speed Trains 5.2 MB

Depew, NY 1

1947	Large All-Relay Interlocking on the New York Central 2.5 MB

DeQueen, AR 1

1947	Railroads Request Relief from the ICC Signal Order 365.7 KB

DeQuincy, LA 1

1943	Signals Ordered on the Kansas City Southern 1.4 MB

derailment 1

1944	New York Central Installs NX Interlocking at Utica 5.7 MB

derails 3

1921	Derails: Are They Good or Bad? 350.6 KB
1939	ICC Permits Removal of Derails 1.1 MB
1929	The Year 1928 in Retrospect and the Outlook for 1929 1.5 MB

Derby Jct., CT 1

1960	News briefs. 1960-07 845.4 KB

Derby, CO 1

1947	Burlington Concentrates CTC Control at Division Headquarters 840.8 KB

Derby, CT 1

1922	Flashlight Crossing Signal 280.8 KB

Des Moines Union 1

1960	Fourteen RRs adopt new operating code 945.4 KB

Des Moines, IA 2

1932	A Call-On Signal Is Different from a Stop and Proceed Signal 667.6 KB
1935	Auto Stop Installed on C&NW 7.2 MB

Des Plaines Valley line 1

1911	General News (August 1911) 557.3 KB

Des Plaines, IL 7

1958	Crossing protection program saves 59% 553.4 KB
1943	Gates at Three Crossings on C&NW 3.4 MB
1948	Gates at Three Crossings on Soo Line 1.8 MB
1911	General News (August 1911) 557.3 KB
1913	New Block Signaling on the North-Western 1.8 MB
1919	The Night Signal Indication 335.6 KB
1931	Three-Track Signaling on 13.5 Miles of the C&NW 5.4 MB

Deshler, OH 1

1932	Centralized Traffic Control on the Baltimore & Ohio 4.4 MB

desk lever interlocking 5

1934	Desk-Lever Interlocking Installed on Canadian National 1.2 MB
1922	New Desk-Type Circuit Controller 1.6 MB
1958	RS&C 50th anniversary: Signaling ... manual to automatic 2.0 MB
1951	Simple Interlocking Saves Many Train Stops 375.6 KB
1929	Simplified Electric Interlocking Plant on Michigan Central.pdf 3.6 MB

detector bars 3

1932	A Detector Bar Fails 1.5 MB
1932	Detector Bars in 1932 419.4 KB
1935	New Interlocking in the Chicago Loop 4.0 MB

detector circuit 1

1959	Kinks. 1959-11 258.3 KB

detector locking 1

1959	Kinks. 1959-11 258.3 KB

detectror locking 1

1922	Work in Signal Field Shows Gain Over 1920 784.5 KB

Detroit & Toledo Shore Line 1

1947	Territories Involved in the ICC Signaling Order 388.2 KB

Detroit Belt 1

1936	Crossing Protection Includes Signals for Directing Trains 17.0 MB

Detroit River tunnel 3

1937	J. C. Mock Retires 1.4 MB
1940	New Interlockings at Windsor, Ont. On the Michigan Central 14.1 MB
1911	Railway Signal Association Convention: Committee I: Signaling Practice 3.8 MB

Detroit Union Belt 2

1955	Crossing protection for 16 streets 371.1 KB
1955	Interlocking Expedites Terminal Moves 1.6 MB

Detroit United 2

1915	New Interlockers on the Flint Belt Line 2.2 MB
1922	News of the Month. 1922-09 562.2 KB

Detroit, MI 18

1958	Central opens Young Yard 2.5 MB
1955	Crossing protection for 16 streets 371.1 KB
1936	Crossing Protection Includes Signals for Directing Trains 17.0 MB
1926	DT&I Interlocking Machine Nickel-Plated When Rebuilt 602.1 KB
1939	Interconnection of Train Signals and Crossing Protection 1.1 MB
1955	Interlocking Expedites Terminal Moves 1.6 MB
1931	Michigan Central Makes Extensive Improvements in Signaling System 3.3 MB
1960	News briefs. 1960-07 845.4 KB
1961	News briefs. 1961-11 1.3 MB
1922	News of the Month. 1922-01 315.5 KB
1922	News of the Month. 1922-02 323.2 KB
1953	Remote Control Interlockings Improve Terminal Operation 551.4 KB
1937	Route Control Interlocking – A New Signaling Development 2.9 MB
1960	Signal construction steady in 1959 385.2 KB
1959	Signaling moderate during '58 528.6 KB
1929	Simplified Electric Interlocking Plant on Michigan Central.pdf 3.6 MB
1924	Study of Train Control on the Michigan Central 2.1 MB
1946	War-Time Replacement of Interlocking on Pere Marquette 3.4 MB

Detroit, Toledo & Ironton 7

1959	AFO circuits protect crossing 554.0 KB
1941	DT&I Installs Automatic Interlocking 5.0 MB
1926	DT&I Interlocking Machine Nickel-Plated When Rebuilt 602.1 KB
1932	Electric Interlocking Constructed by the Nickel Plate 1.4 MB
1927	Half Interlocker on DT&I 565.6 KB
1963	News briefs. 1963-11 1.4 MB
1965	News briefs. 1965-07 788.3 KB

Dett, Rhodesia 1

1965	Rhodesia has 1215 miles of CTC 949.2 KB

Dett, Zimbabwe 1

1965	Rhodesia has 1215 miles of CTC 949.2 KB

Deutsche Reichsbahn 1

1929	Optical Features of German Train Control Reflect Ingenuity 3.6 MB

Deval, IL 1

1931	Three-Track Signaling on 13.5 Miles of the C&NW 5.4 MB

Devon, WV 1

1940	Centralized Traffic Control Solves Problem on the Norfolk & Western 7.5 MB

Dewey, IN 1

1948	CTC Keeps ‘em Rollin’ on C&EI 2.1 MB

Dexter Jct., MO 6

1954	CTC Increases Capacity of Double Track 4.2 MB
1947	Railroads Request Relief from the ICC Signal Order 365.7 KB
1941	Signaling on 47 Miles of St. Louis Southwestern 12.6 MB
1944	St. Louis Southwestern Installs Centralized Traffic Control 6.9 MB
1944	Track Circuits on Passing Tracks in CTC Territory 941.8 KB
1957	Why Cotton Belt installed CTC on entire main line 914.0 KB

Dexter, MO 1

1954	Why Cotton Belt Installed CTC On 429 Miles of Single Track 4.0 MB

Diamond St., Philadelphia, PA 1

1964	Interlocking: New Solid State Coding System Is Fast 1.7 MB

Diaz, AR 1

1947	Railroads Request Relief from the ICC Signal Order 365.7 KB

Dickinson, ND 1

1922	News of the Month. 1922-12 388.1 KB

diesel generator backup 1

1965	Rhodesia has 1215 miles of CTC 949.2 KB

digital simulation 1

1961	Digital Computer Simulates CTC Dispatcher 2.8 MB

Dillon, MO 2

1947	Frisco Moves CTC to One Office 481.1 KB
1944	St. Louis-San Francisco Installs Centralized Traffic Control 8.3 MB

Dillon, NM 1

1922	Signal Construction on the Santa Fe 797.6 KB

Dilworth, MN 3

1962	News briefs. 1962-07 494.2 KB
1963	News briefs. 1963-10 497.4 KB
1922	News of the Month. 1922-05 426.4 KB

direct current relay 1

1916	The New Ziegler Relay 396.2 KB

disc signals 3

1950	CTC on the Reading 6.6 MB
1935	Obsolescence in Signaling 3.4 MB
1912	The Automatic Signal and the Local Circuit 1.9 MB

Disneyland 1

1959	Monorail is signaled electronically 573.9 KB

Disneyland monorail 1

1959	Monorail is signaled electronically 573.9 KB

dispatcher centralization 1

1965	Merging divisions require changing circuits 335.5 KB

dispatching circuits 1

1962	Centralization – Dispatch Circuits Are Changing 1.3 MB

distant signal repeaters 1

1959	What's the answer? Repeater signals 691.6 KB

distant signals 3

1957	How long sidings save train time 465.2 KB
1934	More on Distant Signals 598.6 KB
1940	Southern Pacific Petition Denied 3.0 MB

Divide, NY 1

1963	News briefs. 1963-04 896.6 KB

Divine, IL 1

1934	Spring Derail for Drawbridge Protection 535.0 KB

Division Street, Chicago, IL 3

1911	Interlocking on the North Western Terminal 7.6 MB
1925	Maintenance on C&NW Terminals 12.5 MB
1911	Signaling and Interlocking on the North Western Terminal in Chicago 1.1 MB

Dix, IN 1

1960	News briefs. 1960-07 845.4 KB

DK Cabin, WV 1

1955	C&O Consolidates Interlockings 3.2 MB

DM code transmitter 1

1940	New Code Transmitter 2.1 MB

DN-11 relay 1

1940	Plug Couplers for Relays and Signals 1.3 MB

DN-22L relay 1

1936	Light-out Relay for AC or DC 2.3 MB

DN-22P power transfer relay 1

1936	Power-Transfer Relay for Crossing Signals 3.5 MB

DN-26 relay 1

1950	Retained-Neutral Neutral Relay 3.4 MB

DNL-41 relay 1

1935	An Under-Voltage Relay 1.2 MB

DNL-46 relay 1

1937	New Devices- March 1937 18.1 MB

Dock Jct., PA 3

1955	New York Central’s CTC – It’s Four Tracks to Two 4.1 MB
1955	News briefs. 1955-08 830.4 KB
1957	Where Two Tracks Do the Work of Four 3.2 MB

Doctortown, GA 1

1955	News briefs. 1955-08 830.4 KB

Dodson, KS 1

1922	Work in Signal Field Shows Gain Over 1920 784.5 KB

Dodson, MO 1

1924	Controlled Manual Block Signaling With Train Control 5.5 MB

Dodson, MT 4

1960	News briefs. 1960-01 1.1 MB
1960	News briefs. 1960-03 1.9 MB
1960	News briefs. 1960-06 1.2 MB
1960	News briefs. 1960-07 845.4 KB

dog charts 1

1916	Method for Checking Mechanical Locking 322.8 KB

Dolton, IL 2

1925	Division Train Control Installation on C&EI Approved by ICC 2.9 MB
1920	Largest Saxby & Farmer Machine in the United States 1.6 MB

domino system 1

1962	Control Panels 243.4 KB

Doran, MN 1

1957	GN CTC's 175 miles of mainline 635.9 KB

dot matrix 1

1964	Train Describers: A step toward ATI 2.1 MB

Dothan, TX 1

1960	T&P moves CTC machine 78 miles 423.0 KB

Dotsero, CO 4

1943	CTC on 107 Miles of Single-Track on the Rio Grande 9.7 MB
1955	One CTC Machine Replaces Three 451.9 KB
1944	Rio Grande has Longest CTC 9.2 MB
1944	Signals Direct Trains at Junction On the Denver & Rio Grande Western and the Denver & Salt Lake 2.8 MB

double filament lamps 1

1937	New Devices- March 1937 18.1 MB

Douglas Park Line, Chicago, IL 1

1956	Automatic Crossing Gates on CTA Are Interconnected with Street Traffic Lights 5.1 MB

Dove, IA 1

1951	Single Track with CTC Replaces Double Track on Milwaukee 586.0 KB

Dover, NH 2

1965	News briefs. 1965-10 1.1 MB
1965	News briefs. 1965-11 1.2 MB

Dover, NJ 1

1931	The Signaling of the Lackawanna Electrified Territory 5.9 MB

Downers Grove, IL 3

1925	Excellent Results for 35 Years on Burlington 1.5 MB
1931	New Control System Used at Electric Interlocking on the Burlington 3.5 MB
1954	New Wayside and Cab Signaling 753.2 KB

downstream adjacent crossing 1

1965	GCPs can be used for various types of grade crossings 369.4 KB

Doyle, KY 1

1947	CTC Down by the Ohio 2.7 MB

Doylestown, PA 2

1963	News briefs. 1963-12 429.2 KB
1931	Re-Signaling of the Reading Electrified Territory 778.0 KB

DP-14 relay 1

1940	Plug Couplers for Relays and Signals 1.3 MB

DP-20 relay 1

1950	Retained-Neutral Neutral Relay 3.4 MB

DP-21 relay 1

1950	Retained-Neutral Neutral Relay 3.4 MB

Dr. William Churchill 1

1949	A Century of Signal Glass Developments 4.2 MB

Dr. William Robinson 1

1943	Progress in the Use of Coded Track Circuits 1.6 MB

drafting 5

1940	Drafting Boards 1.8 MB
1916	Method for Checking Mechanical Locking 322.8 KB
1937	Prepare for Construction 1.2 MB
1909	Willson's Gummed Paper Letters and Figures 170.0 KB
1909	Willson's Gummed Paper Letters and Figures 598.7 KB

drafting room 2

1910	Drafting Room Practice in the Signal Department 1.3 MB
1910	Supplemental Notes on Drafting Practice 382.8 KB

dragging equipment deectors 1

1960	News briefs. 1960-10 1.8 MB

dragging equipment detections 1

1964	News briefs. 1964-10 768.6 KB

dragging equipment detector 2

1961	Railroad Will Pay For CTC Out Of Accrued Savings 842.9 KB
1947	Southern Pacific Installs CTC 990.2 KB

dragging equipment detectors 13

1965	AAR and RLEA reply to RS&I exceptions 858.7 KB
1950	Audible Warning Sounded When Dragging Equipment Detectors Operate 4.2 MB
1957	CTC on the SP has special devices 518.8 KB
1939	Drag Detectors Protect Bridges 3.2 MB
1959	Fewer wayside observers makes automatic hazard detection necessary 1.1 MB
1960	News briefs. 1960-11 875.5 KB
1963	News briefs. 1963-12 429.2 KB
1964	News briefs. 1964-07 833.0 KB
1965	News briefs. 1965-06 1.2 MB
1958	RS&C 50th anniversary: Railroad communications ... from Morse to microwave 3.3 MB
1949	Signal Indications to Stop Trains When Dragging Equipment Detectors Operate 922.0 KB
1958	Signaling to cut expenses in '58 411.4 KB
1939	Special Aspects for Detectors 937.0 KB

drawbridge 4

1935	Accident at Drawbridge 1.4 MB
1939	Electric Interlocking on the New Haven 2.1 MB
1941	Southern Pacific Installs Interlocking at Drawbridge 6.3 MB
1929	Trap Circuit for Drawbridge 980.8 KB

drawbridge interlocking 1

1947	Drawbridge Interlocking on the Elgin, Joliet & Eastern 647.3 KB

drawbridges 2

1931	Chicago, St. Paul, Minneapolis & Omaha Eliminates Nearly 20,000 Train Stops Annually 767.7 KB
1939	Drag Detectors Protect Bridges 3.2 MB

Drayton Hall, SC 1

1964	News briefs. 1964-05 1.0 MB

Driftwood, PA 1

1937	Ends of Double Track Controlled by CTC 12.4 MB

drill signals 1

1957	Consolidation cuts costs 1.1 MB

Dryden, G. H. 4

1946	G. H Dryden retires 455.7 KB
1911	Letters to the Editor: A Difference of Opinion 740.1 KB
1928	Personal Mention: G. H. Dryden 432.7 KB
1927	The Color Position Light Signal (poem) 435.2 KB

Du Quoin, IL 5

1961	News briefs. 1961-12 978.0 KB
1962	News briefs. 1962-06 989.1 KB
1962	News briefs. 1962-07 494.2 KB
1963	News briefs. 1963-03 790.6 KB
1965	News briefs. 1965-01 2.0 MB

dual control switches 1

1960	Fourteen RRs adopt new operating code 945.4 KB

dual-control 2

1956	Switch Machines for CTC 2.0 MB
1956	Switch Machines for CTC 985.3 KB

Dubbo, New South Wales, Australia 1

1922	Single Track Signaling in Australia 527.7 KB

Dublin, VA 1

1950	Neon Lighting For Crossing Gate Arms 3.1 MB

Dubuque, IA 4

1942	Automatic Signal Program on the Illinois Central 4.6 MB
1911	Automatic Signals on the Chicago Great Western 7.4 MB
1965	Midwest RRs fight the weather 914.4 KB
1936	Signals Installed at 26 Crossings in Dubuque, IA 13.8 MB

Duck Creek, WI 1

1929	C&NW Employs Centralized Control To Speed Up Trains 3.0 MB

Dudley, MO 1

1922	News of the Month. 1922-02 323.2 KB

Duluth, Missabe & Iron Range 7

1964	Cars identified automatically 512.0 KB
1944	CTC Speeds Ore Traffic On the DM&IR 4.6 MB
1962	DM&IR Consolidates CTC Control Miles 384.7 KB
1954	New Interlocking on Leads to Docks Saves Time for Ore Trains 2.9 MB
1961	News briefs. 1961-10 1.0 MB
1959	Pushbutton console for CTC 785.3 KB
1961	Survey Tells How Railroads Use Hotbox Detectors 1.8 MB

Duluth, MN 5

1964	Cars identified automatically 512.0 KB
1944	CTC Speeds Ore Traffic On the DM&IR 4.6 MB
1962	DM&IR Consolidates CTC Control Miles 384.7 KB
1915	Duluth Terminal Trestle Signaling 2.3 MB
1954	New Interlocking on Leads to Docks Saves Time for Ore Trains 2.9 MB

Duluth, South Shore & Atlantic 2

1960	Fourteen RRs adopt new operating code 945.4 KB
1960	What’s the answer? Automatic OS 354.1 KB

Duluth, Winnipeg & Pacific 1

1922	News of the Month. 1922-09 562.2 KB

Dumas Jct., TX 1

1963	News briefs. 1963-01 951.3 KB

Dumas, MO 1

1922	News of the Month. 1922-09 562.2 KB

Dunbridge, OH 2

1965	News briefs. 1965-01 2.0 MB
1965	News briefs. 1965-06 1.2 MB

Duncannon, PA 1

1963	News briefs. 1963-01 951.3 KB

Dundas, OH 1

1962	News briefs. 1962-11 468.1 KB

Dundee, VA 1

1962	News briefs. 1962-10 461.7 KB

Dunfee, IN 1

1928	Early APB Signaling 408.5 KB

Dunkirk, NY 1

1955	News briefs. 1955-08 830.4 KB

Dunkirk, OH 3

1964	News briefs. 1964-10 768.6 KB
1965	News briefs. 1965-01 2.0 MB
1965	News briefs. 1965-06 1.2 MB

Dunmore, Alberta 1

1947	Canadian Pacific Installs Absolute Permissive Block 774.8 KB

Dunn, John H. 3

1958	RS&C 50th anniversary: Foreword 502.5 KB
1958	RS&C 50th anniversary: Looking ahead 652.9 KB
1958	Six editors in 50 years 253.5 KB

Dunsmuir, CA 1

1944	Railroad Applications of Electronics 1.9 MB

Duplainville, WI 1

1960	What's the answer? Snow shields 424.6 KB

Dupo, IL 1

1955	Crossing gate protection with indicators for train movements 432.4 KB

Durand, MI 2

1953	Grand Trunk Installs CTC on 37 Miles of Busy Single Track 3.5 MB
1958	One track does work of two 521.4 KB

Durango, IA 1

1911	Automatic Signals on the Chicago Great Western 7.4 MB

Durham, IN 1

1960	News briefs. 1960-09 756.9 KB

Durham, NC 1

1950	Neon Lighting For Crossing Gate Arms 3.1 MB

dust storms 1

1935	Signaling in Dust Storms 2.3 MB

Dutton, George B. Jr. 1

1950	Approach Distances and Times 5.5 MB

dwarf signals 5

1937	Approach Locking on Dwarf Signals 1.2 MB
1951	Burlington Installs Extensive Interlocking at Kansas City 1.0 MB
1947	How Low Is a Dwarf? 438.7 KB
1937	Phantom Indications of Dwarfs 1.3 MB
1960	What's the answer? Dwarf signals 511.5 KB

Dwight, IL 1

1934	Simplified Interlocking Speeds Train Operation 1.9 MB

dynamic braking 1

1965	Transit vehicles set for automatic running 182.7 KB

dynamic indication 2

1961	Dynamic Indication 254.1 KB
1962	Dynamic Indication 211.7 KB

Railway Signaling: D