Another use of the poles was to carry quarter, half, three-quarter, and mile markers. The SLSF had forty poles to the mile, and every tenth one was marked. (If you were checking your speed, and the train was creeping along, you did not have to wait forever to get to the next marker; if it took you one minute to get from one pole to the next, you knew that you were covering a mile and a half every hour.) The UP and other roads still have posts every quarter mile, but they serve no other purpose.
RWM, thanks for the brief history. It is somewhat sad to see the abandoned wires along a right of way, but we know that it is not worth anybody's time to recover them.
Johnny
Thanks guys..
In very rough terms:
1850-1900: Communications only, first telegraph, then telegraph and telephone
1900-1920: Addition of simple signal circuits to the communications circuits. These signal circuits are signal-to-signal and convey information to a given block from the adjoining blocks only. There aren't any long-haul signal circuits. Almost all signals were battery powered due to lack of widespread availability of commercial power.
1920-1940: In some instances, power lines are added (usually D.C.) to power wayside signal installations. But many remain battery only.
1940-1960: Power lines are broadly installed to the pole lines, both D.C. and A.C., and the battery-only wayside signal installations decline rapidly in prevalence. CTC code lines are added to many pole lines, on lines where CTC is installed.
1960-1970: Communications lines rapidly disappear as commercial telephone and railroad microwave systems replace the pole line telephone circuits.
1970-1980: Code lines rapidly disappear as railroads convert to microwave, HD Linker, and Bellco circuits for transmitting code information. D.C. power circuits disappear quickly as A.C. utility drops become prevalent.
1980-2000: Signal circuits rapidly disappear as railroads convert to electrocode (which is in the rail) or HD Linker.
2000-present: More and more, all that remains is power only, and usually now it is new A.C. on a new pole line, not the old pole line.
Much of what is still out there today on the old pole lines is dead. The wires remain but the volts are gone. Most of these are iron wires or iron-core wires, and thus of meager value for scrap whether by railroad forces or thieves. Usually the power lines were copper, and those power lines that remain in service are usually hot.
This is the typical pattern on the preponderance of U.S. railways. Others might add the exotic and exceptional.
Switch machine battery chargers have a very low power draw. The machines throw only occasionally. They have a large battery capacity to generate high amperage, but it only lasts for a few seconds. The big power-consumer is the switch heater, whether calrod or forced-air, gas-fired.
RWM
You don't point to a picture so I can only assume you are referring to those normally found along railiroad rights of way, especially in years past. Most of them carried telephone, telegraph, and signal circuits. A railroad had its own communicaitons network from one end of the railroad to the other plus branches so there were local lines, several dispatcher lines, trackside phones, division lines, and corporate lines plus others including spares for both telephone and telegraph. Then there were sgnal circuits which were based on the equipment and manufacturer or system used, et al.
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What is the purpose of those wires? To carry the power for the signals and switches?
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