Re: Telegraph Components

The first photo is a typical "mainline sounder." A morse code key on the sending end sends voltage and current down the telegraph line. This current energizes the coil to pull down the bar between the two coils to make the click, click, clack sound. However, you can't send morse code down a line for indefinite distances - the resistance of the wires (never mind bad insulators or rain) eventually reduces the voltage to the point where it no longer energizes the sounder coils. To correct this, a "relay repeater" is used to amplify the telegraph signals. Your second photo looks like a typical Western Union relay repeater circa. 1900-1920s. The 150 ohms is the key, in that the coils will energize with very weak telegraph signals, which pulls in the bar running underneath the horseshoe fixture. A fresh battery is connected to the horseshoe, such that when the weak signal pulls in the coil, a fresh battery with full voltage and current will repeat, or amplify, the morse code onto the line for the next 100-200 miles. The lever on the left, as shown, is holding the coil contactor in it's operating position for the coils to pull it in. Moving that pivoted lever causes the contactor to move farther away from the coils to disable the repeater. This was used to keep certain telegraph messages, such as specific to your station, from being passed on further down the line to save that precious battery power. Also, the repeaters were used for putting smaller branch circuits onto the mainline circuit.

I don't know exactly how D&RGW organized their circuits from the Denver office, but there was a repeater station, likely in Pueblo, that would repeat the messages onto the proper circuit. Each message had a preamble that identified the destination station, or circuit, to receive the message. The repeater operator, upon hearing the preamble, would activate the proper relay repeater(s) to pass the message on, such as to Salida, the Monarch Branch, or on to Alamosa. The repeater at Alamosa would likewise amplify the signals to pass it on to the San Juan branch, with another repeater likely in Chama. I do know the Santa Fe Railroad had a major relay repeater station in Albuquerque, the old building still there (at least two years ago). There were a dozen morse code operators listening to all incoming messages and activating the proper relay repeaters to amplify the signal and pass them on to the proper circuit.

I'm sure doing a web search on "railroad telegraph repeaters" or similar will reveal many types of repeaters, and perhaps the exact Western Union model you have.

AR "._._." (morse code for "That's all folks")

73, Paul "Moosie68" NA5N (amateur extra call sign; 100% morse code operator)