Railway Open Wire & Signalling

Now deceased BNSF open wire near Enid, Oklahoma.

Romancing the Wire . . . Railroad Style


During the Age of Steam, open wire was king!

Junction between an open wire lead and a pulp multi-pair cable on H-fixture Terminal Structure. Taken from suggested specifications of the American Railway Association (now the Association of American Railroads). Circa: 1918.

Double A Terminal Box (wooden) with two-door entrance. Relic preserved of Chicago-Northwestern Railway Company, 1920s. Note three board splicing balcony seat.

Modifed Union Pacific Railway Communications Department H-Fixture Dead-end Assembly. The “X” brace is standard electric distribution-issue Hughes Brothers of Seward, NE. Hughes Bros. originated the first standardized “X” bracing in the late 1920s.

Carry-through X-Fixture for achieving dead-ends for signal circuit installations.

Underslung Alcoa Case 6-inch point-type transposition bracket (top arm right end). Uniquely applied to this Gainesville, Texas location. Burlington-Northern Santa Fe Railroad System. Linewrecked mid-2000s.

How buried pulp cable was connected to aerial wire with vertical distributing boxes, c. 1925.

One of the great locomotives of the 20th Century…the UPRR No. 844!

The railways of the United States might be called the “next-in-line” pioneers of the open wire heritage we have today.  Since the early days of the telegraph, the planting of poles along a railroad right-of-way was a technical marriage made in heaven.  What began in the 1840s, has persevered through the last century and most likely will end when the last railroad openwire is decommissioned in 2020. 


Railways, like their counterparts in the civilian telecommunications field, may have designed and constructed aerial wire plant which appeared at first glance to be identical, but often differed markedly not only between American Railway Association (now the Association of American Railroads) and Bell, for example, but also differed between competing railroad corporations.


The American Railway Association’s Communications Section, originally formed as a gathering of various railroad telegraphers’ clerks and managers, quickly became an sub-group of the ARA.  By the early 1900s, the new name: Communications Section of the ARA, identified transportation communications more broadly.  Now, it incorported not only telegraph, but leased telegraph and telephone, signalling, carrier systems and data transfer over aerial wires.


When the Communications Section annually met every other year or so, it published transactions of their meetings.  Members met representing various member railroads such as: the Great Northern, Union Pacific, Burlington & Quincy, Chicago Northwestern, Rock Island, Grand Trunk Railway System, Illinois Central Railroad, Philadelphia & Reading Railroad, Atchison, Topeka & Santa Fe, Missouri, Kansas & Texas Lines, New Haven & Hartford Railroad, Cleveland, Cincinnati, Chicago & St. Louis Railroad, Lehigh Valley Railroad, New York Central Railroad, Toledo & Ohio Central Railroad, Milwaukee & St. Paul Railroad, Baltimore & Ohio Railroad, Southern Pacific Lines, Southern Railroad Lines, Pittsburgh & Lake Erie Railroad, and a host of equal and smaller lines.


Not only the railroads, but any organization whose work involved communications and railroad relationships.  For example, one could cite such facilities owned and operated by Western Union Telegraph Company, AT&T, Postal Telegraph Company, Overland Telegraph Company, Harland Engineering (Montreal, Canada), and others.


At the regulatory level, members included, of course, the American Railroad Association, the United States Railroad Administration (various regional offices as well), Marconi Wireless Telegraph Company (of which David Sarnoff, was the Commercial Manager in New York at the time [1919]), as well as a host of smaller telegraph clerks associations and state groups.


The reason for including companies such as AT&T, engineering consulting firms and manufacturers of equipment, was due to the fact where railroad facilities were found, various other facilities also paralleled, crossed, and challenged existing railroad signal circuits.  It was important to comprehend the intricate nature of existing major toll, exchange and other civilian telecom facilities and their impact on nearby railway signal/communications.  Also, the importance and impact of inductive crosstalk could not be underestimated when various facilities were intertwined down a narrow easement including railroads, roadways, telegraph, telephone, carrier systems and electric power utility systems within a tight 75′ right-of-way.  Additionally, there were crossings of various electric power transmission, distribution lines and intermediate substations’ impact on AT&T, W.U., Independent telco and other railroad systems’ lines.

2013 illustration of UPRR H-Fixture Support with dead-ending systems post-1924. Note unused drop bracket, rare for this type of construction.

This was the general consensus of American Railway Association Communications Section leadership on dead-ending line wire. Circa 1924.

Chicago-Northwestern Railroad Company’s H-Fixture equipped with double arms and terminal. Note insulated drive rings of white porcelain for bridling connectors to open wire pairs.

Method of mounting medium box with balcony, c. 1923.

Canton, South Dakota terminal (deceased line) for Milwaukee Road railway. From the 1940s.

1940’s ARA Communications Section specification terminal structure. Note the clear glass Hemingray insulated shackles at bottom right.

Note the double arms for double deadends so leads can be spliced into the signal circuits. Southern Pacific Railway, Arizona.

Detail of insulated over-arm glass spool shackle. Hemingray insulator spool, c. 1956.

5-kV heavy dead-end shackles for UPRR 2.4-kV Delta Centralized Track Control circuits. Note double-deadends for insertion of disconnect switch blades mounted on standard cutout holder. ANSI gray spools denote installation after 1966.

Typical multi-skirted 5-kV wet process spool insulator and shackle for dead-ending. Joslyn Mfg. & Supply Co. c. 1950s.

Dimensions of the larger signal circuit dead-end multi-skirted spool insulator rated 5-kV.

Tangent construction where signals are connected to the track control system. Two pole construction is not necessary.

Mounting method of hanging large cable terminal boxes and balconies.

Side profile view of Double A Box with doors open. Chicago-Northwestern Railway Company, 1920s.

Committee Membership & Technological Development

Aside from the five major Officers of the ARA and an Executive Committee enlisting the names of nineteen other leadership positions, various committees were coordinated by a General Committee.  The Chairman and Vice Chairman would lead eleven sub-officers in directing meetings where by the Telegraph & Telephone Division would meet, discuss developments (both technical and administrative) and then publish their deliberations in the Proceedings.  Officially called Proceedings of the Session of the American Railway Association Telegraph and Telephone Section, and specified as to the meeting place of the congress and to the times held, these are masterful records of the ARA’s state of the art processes and proceedures as regarding many areas, but primarily for our use here, as information relative to signals and communications.


Here are some of the topics which each committee was assigned to deliberate and conclude final decision-making on the most current specifications, proceedures, and agreements with which their various membership decided upon:

Construction & Maintenance – Outside Plant

Maintenance & Construction of Pole Lines

Wire Crossings

Underground Construction


Construction & Maintenance – Inside Plant

Protection Against Electrolysis

Protection Against Lightning or Electric Light & Power Circuits

Telegraph and Telegraph Development

Message Traffic

Inductive Interference

Editing [of the final Proceedings to be published] 

Iowa Interstate 29 foreground with Omaha, Nebraska background. Special long span ARA communications heavy duty double-armed H-fixtures to carry line wires featuring “knee and V-bracing.”

Typical Break Iron

Break Irons were made . . . of iron!

Single arm later style used by railroads in the 1940s, which was available in an extended double-arming style as well.

Close-up of UPRR alley-arm structure placed to avoid obstructions. Note the structure also performed a dead-ending role with the spool-type brackets installed properly.

Spool type dead-end (extended) for double arm dead-ends. From Union Pacific Raiload system, c. 1940s. Spools were secured by the bolts and would not spin as in other clevis units.

Actual use by Union Pacific Railway at Rossville, Kansas on a unique alley-armed dead-end structure (decommissioned).

Illustrated above is a typical Break Iron, used for the termination of pairs by railway signal systems, using a short iron strap drilled for short shank one inch diameter insulator pins.


Note the unique use of split knob porcelains, so common in residential construction of the period and known as part of the “knob and tube” indoor wiring system.  Unfortunately, these only offered space for one pair of bridle wires. 


Many railroads used the insulated screw-in wire holders with porcelain inserts which were large enough to offer numerous bridle wires space when staggered about 8″ to one foot apart at the bottom of the arm.  One is pictured below:

Insulated Drive Rings for bridle wire runs beneath the arm.

Insulated drive rings in practice. Bridle wire carried from open wire pairs inside rings to terminal enclosure.

Under crossarm and depot station bridling run insulators. Macomb-Illinois Porcelain (1940s) left and Hemingray (1950s) clear glass on right.

Majestic ruins in western Kansas.

ANSI Gray (1966 and after) over-arm insulated shackle for railway use.

Large Terminal Box arrangements of binding post connections and cable entrances c. 1925.

The UPRR No. 844 passes into history along with railway aerial wire & cable…

Now, this was just the Section on Communications.  The ARA, in addition to the Executive Committee, the Committee on Nominations and the Advisory Council, the organization included the following Sections:


Section I: Operating.  This organization affected practices such as TRain Rules, Rules for the Operation of Interlocking and Block Signals, Rules for Detoruing of Trains, Protection of Grade Crossings,Practices affected by Standard Time, and other details relative to the “advancement of the efficiency of the telegraph and telephone departments of railways.

Section II: Engineering. Those processes advancing the knowledge “pertaining to the scientific and economic location, construction and maintenance of railroads.”

Section III: Mechanical. Actions relative the advancement of “knowledge concerning the principles of construciton, maintenance and serice of the rolling stock of railroads.”

Section IV: Traffic.  Considerations of questions “affecting the relations of the operations of railroads and the public.”

Section V: Transportation.  Those matters “affecting the efficient utilization and interchange of equipment, the handling of railroad business mail and kindred subjects.”

Section VI: Purchases & Stores.  “Consider and report upon all questions affecting the purchasing, selling, storing and distribution of materials and supplies and kindred subjects.”

Section VII: Freight Claims.  Those questions “affecting the prompt and lawful settlement of freight claims with claimants and between carriers; also to study claim causes and application of preventative measures.”

Terminal pole where a junction between open wire and underground pulp cable c. 1925.

Intermediate terminal on 30-wire signal lead, Western Kansas.

Joslyn over-arm brown porcelain insulated clevis.

Method of using double arming dead end shackles on aerial wire c. 1923.

Towering ruin distinctly illustrates use of Aerial Distributing Boxes for 3 arm and larger poles, c. 1925.

How break irons allowed for bridle wire connections to Distributing Box, c. 1919.

Here illustrated, is one of the few vertical distributing box installations left in the Topeka, Kansas area in a state of partial deterioration.  The stout cable with the red marker is a fiber CATV system link and Cox is using this old Missouri Pacific Railroad pole as a support.  The vertical boxes were made from various woods, and the knob-and-cleat house-wiring insulators were also employed.  


Note that the box was probably made in the railroad’s own communications’ shops and the porcelain terminal strips with binding posts bought from local or regional railroad electrification suppliers. American Telephone Supply, Crouse Hinds and other companies sold this hardware to be installed.


One noteworthy thing about railroad facilities–no matter where they would be found in the United States–was everything was overbuilt. While cities would use lightweight steel or aluminum poles for traffic signals, street lighting standards and fire/police call boxes, the railroads used monumentally rigid iron supports, signal mountings, brackets and other “survive the apocalypse” materials.  Even terminal boxes mounted on poles and crossarms were noteworthy for their survivability as iron.  Insects, too, found them inviting.


Terminal boxes such as these were arrayed throughout the United States to conform to the American Railway Association, Communications Section’s implied and recommended practices. These distributing boxes allowed much working space, were equipped with locking devices (padlocks, mostly) and could be field modified.


Take the Bell, Independent and other commerical telephone companies for example: their lightweight aluminum cans, boxes, terminals and splice enclosures were designed and made for easy installation and tight locking by service people. They could be hung in a variety of ways on cable, on strand, on crossarms and on brackets.  Compare the two types of open wire outside plant between the railways and the telecom organizations. Quite a surprising number of innovative ways of doing things.

One style of Hubbard (Joslyn Mfg. & Supply Co.) Point Type RR bracket.

Another Hubbard Point Type transposition bracket for railway use. Note the terms “RIGHT” and ‘”LEFT.” This pertained to ‘West-to-East Wire Tramp Scheme.

ARA Communications Section Specifications

Typical framing for railway communications and signal structures c. 1919.

This drop bracket design is taken from the American Railway Association and manufacturer’s standards.

Note the two types of standard transposition brackets below.  While we will later consider the broad variety of railroad-type point and lift brackets (which were hugely dissimilar to the standard Bell or Independent company’s vendor choices), consider the very common “drop bracket” and “phantom bracket” below.


While the railroads had the opportunity to purchase from Joslyn, Hubbard, Line Material Industries and a host of smaller pole line hardware manufacturers regionally, their designs incorporated some subtle differences as shown below.  Note the use of upturned pins which converged from the basic steel architecture of the bracket.  There was no flat end, in which a 5/8″ short shank steel pin and cob could be inserted.  Good way of doing things?  Maybe. . . ?

Note below the discrete differences in gaining, roofing poles, as well as transposition bracket styles.  The railroads purchased from the same suppliers as their civilian telecom counterparts, yet specs were just a little different.  For example, the railroads would place the steel 30″ span crossarm braces on the inside of arms while the Independent and AT&T companies placed their steel braces on the face of the wooden crossarm.


Terminals, too, were very different.  While the Bell and other Independents, disavowed use of wooden crossconnect and other terminal boxes, after the 1920s and resorted to steel and aluminum lightweight materials, the railroads maintained use of large overbuilt wooden and then incredibly heavy IRON terminal enclosures.


Pole stepping was done quite differently between the two communications ventures: the use of a steel tower type step–simply a long shank steel bolt with a auger-type base tipped with a spherical head–was used by railroads in the early years.  The typical telco step, with the simple auger-type base, a knarled ring to confirm proper depth of placement into the pole complete with an up-angled end (to prevent slippage by the lineman’s boot), was prevailant through all these years up to today’s style.  The railroads accepted this spec. very sluggishly. 


Aerial cable, when used with open wire facilities, was typically run at the highest point and anchored by a strand over the crossarm open wire circuits below.  This was a unique feature of many railways using the American Railway Association Communications Section standards.


And then . . . there were railroads who just did things . . . differently.  Take Rock Island Railroad, for example, when it operated throughtout the United States central area.  I was once told by both UPRR and Burlington people that if you saw things done in a very unique way, it was probably facilities owned by the Rock.


Additionally, members of the ARA Communications Section were notabsolutely bound by the findings of the Proceedings.  Union Pacific had their way of doing things; so did Burlington & Quincy . . . and KATY, for example.  However, the technical aspects of their operation were probably more consistent with ARA Communications Section proceedures and processes.  There was little leaway where Bell Companies’ specifications and operations were concerned in differing from one another in different locals.  Northwestern Bell lines looked nearly identical to Michigan Bell, or Pacific Northwest Bell.  South Central Bell’s open wire was practically the same as Mountain States.  Bell Companies, like REA-funded mutual and cooperative telephone system organizations, had to conform to both AT&T standards and purchase from approved vendors: namely, Western Electric and other standard suppliers.  REA-funded organizations were required to only purchase equipment from “Borrower Approved” equipment manufacturers, since the REA’s engineering branch had thoroughly tested and placed their approval on such device use.

Here’s our single piece 1940s “Butterfly” bracket.  Note, it too, like the above drop bracket, sports the same architecture.  No separate pins.  Which . . . may have improved the problem of having to stock separate short shank pins.  When standard drop and phantom brackets are ordered, the supplier did NOT supply the pins automatically.  You HAD to purchase them separately.  Perhaps, this design was purposely applied to avoid multiple part stocking problems?

This “butterfly” phantom bracket design was taken from an ARA and manufacturer’s idea.

Lateral view of 6-arm distributing box serving buried pulp cable to open wire.

An ARA “approved” suggestion as to using an “A” fixture on less dense soil.

The railroads were not afraid to try unique solutions to old fashioned problems.  Here we have a modified “A” structure for open wire signal systems.  Note the support features and the lack of an “X” brace.  Properly applied steel braces (30″) are sufficient (with the pole’s cantilevered design), and arms, to afford a strong and resilient structure.

Typical Chicago Northwestern Railway specification 10′ crossarm. Construction after the mid-1950s favored Continental Rubber Works Pony and SEECO DP insulators. Note the 10B arm modified to accept carrier: pins number 1-2, 3-4, 7-8, 9-10. CNW design.

Typical Chicago Northwestern 10B arm sporting Cont. Rubber Works narrow profile insulators. These insulators directly screwed on non-cobbed bare steel pins as thimbles were 1/2″ diameter.

ARA Recommended practices for detailing the use and operation of various circuits on open wire and aerial cable.

More blank forms suggested by the American Railway Association subcommittees on outside plant record keeping..

Typical index card stock with pole head symbols in use c. 1925.

Approved ARA symbols for open wire pole head circuit use designations.

Terminal structure built to ARA Communications Section Requirements: c. 1922

Location in northeast Kansas where ARA distributing boxes acted as buried cable junctions to open wire, c. mid-1920s. Note the canister at top arm left. It was a carrier filter.

C. 1923 Distributing Box with cable connection

Exterior of 1930s style Western Railroad Supply Signal Terminal Enclosure.

Iron WRS terminal enclosure on preserved CNW Railway structure.

Interior of above box. Removed from linewrecked UPRR system near Gorham, Kansas. Circa 1930.

Small terminal box arrangement of binding posts c. 1919.

Typical medium sized terminal box for open wire and cable connections, c. 1919. Note when splicing cable, the first, lowest numbered pairs are used at the top and outside pairs used in descending order to higher numbered quads at bottom.

Hat’s off to Art Lockman, long-time UPRR Repair Shops Foreman, whom I knew when he lived in Iowa.

…good bye–age of steam–good bye open wire…

Railway open wire’s grave.