1900's battery operated grade crossings

[Anonymous]

Does anyone know the history of the battery operated grade crossing signals that were used in the 1900's ? I found a bottle of what used to contain oil that was made by Thomas Edison for maintaining the electolyte in the batteries that ran signals at grade crossings. I would like to get more information on these crossing signals. [:)]
Any information would be greatly appreciated. e-mail me at [e-mail]

Many thanks, Dan

[mersenne6]

Battery operated grade crossings were used wherever there was a need for an operating signal and the cost of running an electrical cable for power was too high. The batteries were mounted on a support behind the signal and it was the job of the maintenance crews to check the condition of the batteries, electrolyte fluid level, charge, etc. The first battery jars were just that - large, thick walled, barrel shaped glass jars about 8" in diameter and about 12" high. Resting on top of the jar was a thick circular ceramic plate to which was affixed the the battery electrodes. The liquid in the battery was "sealed" by pouring oil on its surface in order to retard evaporation. The glass jars were later replaced with an industrial grade plastic (I think it was Bakelite but I can't find the reference).