Robert Wrote:
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> At our local museum we have rigged up the depot
> telegraph keys and sounder with a battery so
> demonstrations of telegraphy can be done for
> visitors. An interesting question has come up
> which I’d like to share here for any help that can
> be provided from the very knowledgeable
> railroaders on this board.
>
> Since the old railroad telegraphs operated with
> battery voltage, which would be DC instead of AC,
> and since DC cannot be transmitted over long
> distances nearly as well as AC, how were the
> signals transmitted reliably over the great
> distances required for railroad operations? I’d
> think this would be especially critical with what
> I understand were pretty low voltage levels of the
> battery sources.
>
> Many thanks for any help you can offer!
>
> Robert

Robert--
Most RR telegraph offices had more than just a KEY and a SOUNDER.. They also had a RELAY and sometimes a REPEATER. Most were manufactured by J.H. Bunnell Co. of New York.
Both the RELAY and the REPEATER had coils that would operate on very faint currents of only a few milliamperes. The line windings of relays were usually hooked up "in series" on down the pole line to the various Stations. When one operator sent a message, that message traveled on down the line. The NEXT relay would take the feeble current and message and "RELAY" it on along. I have complete drawings and specs as to how this worked.
Power supply at each Station was Dry Batteries (usually "Blue Bell" manufactured by Western Electric) or in the case of the early 1900's, "Leyden Jars" using a 'blue vitriol' solution.
For further info, contact me direct: keyrouteken@msn.com

Cheers.

KRK