Vermont Trolleys

[daveklepper]

The lightweights were some of the last streetcars built that had 600 volts in the controllers (one each end) with K-type controllers (I think K-35), and a line-switch (crcuit-breaker) above on the ceiling.  Even earlier cars, like the Brill 1931 Red Arrow cars, had low-voltage control systems controlling contactors for both resistancce insertion and removal and transition from series to parallel.  In the traditional K-Type controller, this is all done manually by the controller handle and contact wipers and copper strips within the controller.

The lighting in the Broadway-42nd Street cars, 551-625, looked exactly like PCC  lighting.  These were the only Third Avenue cars with dropped celings, the others exposed the wood ceilings and had bare-bulb lighting just like the convertables and "box cars" (bowling-alley seating) they replaced.  But the PCC-type glass diffusers were below the usual 32-volt bulbs arranged in a string for 600-volt operation.  The streetcar 32-volt bulbs had a unique feature.  When they failed, they shorted instead of opened.  Thus, lighting would continue even before the single bulb was replaced.  If more than one failed, then the added current and lower resistance would blow a fuse or circuit-breaker for the string.

The Third-Avenue foot brake is a complex story in inself, with push to the floor for release, and removing foot pressure to apply.  Take your left foot off the pedal and emergency brakes apply and the front door opens.  Creeping up to another car in the carbarn, you have your controller on the first point of power, maximum resistance in the motor circuit with all motors in series, and then depress and partially release the brakes with your left foot, inching up to the car ahead, as the automatic air-operated underfloor line-switch cuts in and out, out when any brake pressure is present.  Fun cars to operate, and learned at age 15 in The Bronx.

[Flintlock76]

Bringing this one back to life, we had a discussion going about arc lights.  Were they dimmable, ot not?

Well, I found this interesting video.  Now certainly it's not a trolley headlight, it's a carbon arc searchlight, but the starting process is interesting.  It starts at a dim setting, then the operator reaches inside, throws a switch, and BOOM!  The light goes to the max!  

So it looks like that searchlight had a dimmable option.  Here's the vid...

https://www.youtube.com/watch?v=HWLmKcZtb-4  

Been waiting three days to post this!  Glad the Forum's alive again!

[rcdrye]

Flintlock76

Were they dimmable, ot not?

The short answer is "no".  While it is possible to set an arc lamp to delver varying levels of light, the light level is set by the length of the arc.  Ironically, a short arc, that produces less light, may actually consume more current.

On most electric railways where arc lights were used, they were used outside the city limits.  An incandescent headlight, either built into the dash or hung on the headlight hanger beside the arc light, was used inside city limits. 

[Overmod]

Flintlock76

Well, I found this interesting video. Now certainly it's not a trolley headlight, it's a carbon arc searchlight, but the starting process is interesting. It starts at a dim setting, then the operator reaches inside, throws a switch, and BOOM! The light goes to the max!

What it appears you have is 'brilliant' and 'incredibly brilliant' more than what's normally intended for 'dim'setting.  There is minimum brightness imposed by the physics of the arc and its interaction with the carbon, still brilliant blue-white; I can't tell whether there is a 'starting' current to establish the arc and then a switch to full amperage, or whether there is a setting of the carbon feed that adjusts the length.

A second consideration is that "dimmed" setting on many road vehicles also involves 'dip' -- the original meaning of low vs. high beams.  Some early locomotive headlights had the focus of the parabolic reflector aimed at a fairly close point on the track, as evidenced by early images; it is possible that this was adjustable by shifting the mirror relative to the fixed light source.  It stands to reason -- some reason at least -- that a carbon-arc light could have its light lowered, and some sort of filter or gel interposed in the light path to reduce the glare.

But I doubt you'd dim the arc effectively by tinkering with current supply, and there would be unpleasant effects by trying to modulate the electricity supplied from the DC overhead wire.

[Flintlock76]

Didn't this turn into a fun discussion?

Continuing with the fun, how's about an arc light "Death Ray?"

Wait for it...

https://www.youtube.com/watch?v=u8e_u_xqN30  

I've got to get one of those things to mount of the front of the car.  Then the next time I'm driving at night, and some oncoming idiot refuses to dim his high-beams, will I have a surprise for him!   

[Overmod]

Flintlock76

I've got to get one of those things to mount of the front of the car.  Then the next time I'm driving at night, and some oncoming idiot refuses to dim his high-beams, will I have a surprise for him!

Problem is that the autoignition time for his paint and so forth is too long, a bit like using near-visible EM to make missiles fail.  

What you want instead is something like the system Tom Clancy proposed to take down Japanese tanker aircraft.  A very large capacitor bank discharging into a very large flash tube, mounted in a good front-surface reflector.  Bet they get religion about high beams after that!

I'm a bit surprised something along these lines wasn't used 'back in the day' for streamliner recognition, where a rotating vertical searchlight beam didn't cause enough attention but periodic artificial lightning might have...