Nostalgia & History > What's That Up In The Air?

It's a device, an electric switch, up on a trolley wire to energize a coil in a turnout (track switch) in the street ahead of a streetcar.  When power is being pulled by the trolley pole shoe when it goes through the device the point in the turnout flips one way.  Drawing no power flips the point the other way.  Note, streetcar turnouts have only one point instead of two like standard railroads.  If it does not work the streetcar operator has to get out and physically throw the point with something that looks like a crowbar.  (Correction, some street turnouts have two points.)

This one, and I hope someone can tell us the name of the device, was above the intersection of Girard and Lancaster in Philadelphia, PA on October 10, 2012


Enjoy,
Marty Bernard



Edited 3 time(s). Last edit at 05/29/20 20:27 by MartyBernard.

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MartyBernard Wrote:
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> It's a device, an electric switch, up on a trolley
> wire to energize a coil in a turnout (track
> switch) in the street ahead of a streetcar.  When
> power is being pulled by the trolley pole shoe
> when it goes through the device the point in the
> turnout flips one way.  Drawing no power flips
> the point the other way.  Note, streetcar
> turnouts have only one point instead of two like
> standard railroads. 

In the Twin Cities of Minneapolis-St. Paul this was called an "Electric Track Switch Controller".  A sign was hung ("ELECTRIC TRACK SWITCH") on the span wire close to the controller to remind the motorman.  This was important!  It was wired such that a car passing under it drawing power the switch lined to the curved route, if not drawing power it lined straight.  A motorman who missed seeing the sign was likely to attempt proceeding at track speed thru the intersection, with the result that the trucks would try to take the curve route, while the carbody went in a straighter direction.  Nasty.

> If it does not work the
> streetcar operator has to get out and physically
> throw the point with something that looks like a
> crowbar.
>
Twin City cars carried the bar you refer to, tucked away.  They also carried two longer bars, one each suspended on brackets to the motormans left and right, which dropped thru traps in the floor above each rail.  With these a motorman needn't leave his seat to manually throw a switch, if he stopped in the right spot.

-John

When I worked at SF Muni these were called "Power-On, Power-Off" switches, for obvious reasons!  At Muni they were used for the streetcars and also for trolley coaches. 

Trolley coaches also had a different type of switch-throw mechanism called a "Selectric" that would gauge the angle that the trolley pole was inclined by noting if the two trolley shoes hit the detectors at the same time (straight-through) or at different times (diverging), and throw the switch in the overhead accordingly.

Muni light rail also has a type of switch-throw with a box painted on the street with an electromagnet under the pavement.  A signal light on a pole with a bar cycles between indicators, and the operator  moves the car over the box when the indicator is showing the direction that that vehicle should go.  The electromagnet detects a giant metal object and throws the switch for the direction indicated by the bar signal at that instant.

Lots of options!

LarryDoyle Wrote:

> Twin City cars carried the bar you refer to,
> tucked away.  They also carried two longer bars,
> one each suspended on brackets to the motormans
> left and right, which dropped thru traps in the
> floor above each rail.  With these a motorman
> needn't leave his seat to manually throw a switch,
> if he stopped in the right spot.
>
> -John

I can see how he could throw a left point from his seat, but a right point  ???

Marty

MartyBernard

> I can see how he could throw a left point from his
> seat, but a right point  ???
>
> Marty

Motormen on Twin City standard cars were seated near the center of the car, so there were traps on both sides of him.

On PCC's they did sit further to the left. I don't remember if PCC's had the throw rods.

-John

We on the Los Angeles Railway and Pacific Electric called then 'Brushes".
They looked homemade and looked like Wire Brushes used to clean metal surfaces.
We have and use brushes out at the Southern Calif RR Musem in Perris, Calif..to activate the Wig-Wag signals.

James R.(Jim) Baker
Whittier, CA