Here are shots of the Relays, Batteries and "Switch Motors" used on most Railroads ntil the wide acceptance of "CTC" and more solid state equipment.
The Batteries are more or less the same - some have been upgraded to NiCd, Gell Cells and such - while some of the older Lead-Acid "Wet Cells" have been replaced with newer /refurbed' Wet Cell Lead Acids.
The "Switch Motor" is used on Switch Tracks [Called Turnouts] on Sidings and Crossovers, or Buffer Tracks and interlocks within yards, that are not Manually thrown by the Train Crew.
These are most commonly used to throw the switch over by Remote Control [either by the Dispatching personnel in charge of that District, or by PLC Control in CTC areas] to either "Go Into The Hole" [take the Siding], or to "Crossover" between double maintrack areas, or to enter a Diverging Route [from one District to another].
View of Control Relays inside of a typical "Control House" enclosure. This one was used at a Street Crossing [Tracks cross a Public Street], but is typical of most Control Houses.
Close up shot of the Control Relays.
Shot of some commonly used Batteries. The Batteries are part of an UPS system - which assures their will be available DC power to run signals, throw switches [power the switch motors], keep the Relays functioning, power Street Crossing Gates and Lights, and similar items in case of power failure on the AC input [commonly Utility power].
Each House has a 1200/2400 V x 120 v stepdown transformer. Size is around 5 KVA.
Batteries are connected in Series, to derive 120 VDC - then banks of Series connected batteries are sometimes connected in Parallel when a High Current application requires this approach. These would be at locations with multiple block signals, 4-6 switch motors and lots of Relay Logic to run this stuff!!!
Here's the Switch Motor enclosure, used to remotely control Turnouts.
These enclosures contain 120 VDC Series wound motors and a gear reduction unit.
Motors are like 2 HP or maybe more. Those turnouts are really hard to get moving!!! Especially in snow!!!
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