[PRCo] Track Switch Relay PCCs

[Fred Schneider]

I'm trying to clean up hundreds of e-mails now that I'm in my  
apartment.   This may be redundant in which case feel free to  
delete.   It may, on the other hand, clarify for some of you what was  
already said in which case you may find it useful.

The traditional way of throwing a track switch (except for Toronto's  
necessary or necessity-action scheme) was power to throw it in one  
direction and coast to flip the tongue in the opposite direction.    
Unless the switch was on private right-of-way, the switch contactor  
had to be mounted in the trolley wire in close proximity to the  
switch so that no other car following you could throw it when you  
were already on the switch, and so that you (the motorman) could see  
it throw without having automobiles or trucks or anything else on top  
the switch.   That means the contactor is mounted in the trolley wire  
perhaps 50 to 55 feet back of the switch point, allowing five to ten  
feet to stop the car if it didn't properly throw.    If you mount it  
55 feet back, then a motorman on a sweeper or a single truck car is  
25 feet away from the point when it throws and there is a good chance  
pedestrians may block his view too.

So you don't want a whole lot of room to spare.   On the conventional  
cars you are pulling up to the switch usually with one point of power  
and brakes applied.   The car is completely under control.   If it  
fails to throw you can actually kill power and blead off the brakes  
in ten feet, make a nice smooth stop, open the doors, get out and  
hand throw the switch.

But a PCC car doesn't work that way.   You cannot come up to the  
contactor with one foot on the power and one on the brake.   Brake  
preempts power.   If you push down the brake pedal, the motoring  
relays automatically open under the car and kill power and the  
braking relays close.    Even on the St. Louis Public Service 2-pedal  
cars (some of which later ran unaltered in San Francisco), you could  
not brake and power simultaneously.   You needed to fully release the  
brakes before the cars would take power.  The solution was to install  
a separate resistor on the cars  ... measured about the size of a  
computer keyboard and weighed about two or three times as much ...  
mounted under car.   When you toggled the Track Switch relay it fed  
600 volts through that resistor, essentially a larger electric  
toaster.   It simply used current to make heat.    They were simply  
of sufficient capacity to trigger the average track switch circuitry  
when you went through the overhead contactor.   So you could coast  
through, push the dash switch, and get the same affect as an older  
car powering through with the brakes on.

The installation that always intrigued me was here in Lancaster,  
Pennsylvania, where there were two switches in a row coming into Penn  
Square from the west.   Laurel and Filbert cars had to go to the  
right side of the monument in the square ... that was easy.   They  
only had to throw one switch.   Columbia, Marietta Avenue,  
Elizabethtown, Millersville, College Avenue and West Belt had to  
first throw the switch for the left side of the monument and then  
throw a second switch for one of the two parallel layup tracks in the  
northwest side of the square.   There were two wire contactors, about  
20 feet apart in the trolley wire, on a roughly four to five percent  
upgrade leading into the square.  And the cars ranged from 30-foot  
Birneys to 43- to 47-foot suburban cars.    An extra man, unused to  
the cars, had to be damn good to properly coast and motor or motor  
and motor or motor and coast without having to get down with a switch  
iron.

Fred Schneider