Colour Light staff for trams

tramcar trev

all manner of mechanical apparatus...
I remember on single track sections of some " provincial" tramways there were colour light staff control usually just a red and green light hanging from a span wire usually. At Bendigo I think there was just a green light at the end of the passing loop, no green light and you waited for it to go green.... Anyone got any pics of prototypes? and assuming I can make them (3mm red and green leds encapsulated in a resin "box") how does on get them to work automatically?
 

trammayo

Interested in vintage commercial vehicle, trams, t
24 Oct 2009
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Hi Trev - the only pic I have is of a single light box (below);

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Mick
 

nicebutdim

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With regards to controlling them, Maplin over here sell bt style latching relays and reed switches. Very cheap and easy to wire up. That's for tram passing and green light going out. If the signal is point controlled use supplementary switches or microswitches (indoors use only).
 

dutchelm

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If its for controlling a single line section why not have a pair of LEDs back to back across the track. The red or green will show depending on the track polarity.
 

Neil Robinson

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If running analogue you could use red and green leds in inverse parallel (or red/green bi-colour leds, the same thing in one package) wired to the track section ahead via a 1K ohm 1Watt resistor. Connect so that a tram approaching in the opposite direction (opposite polarity) shows red and it'll show green when the track polarity ahead is O.K. to proceed.
This option, whilst simple, doesn't have an led off mode though unless the relevant section track power is turned off.

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Edit, I see Mike had the same idea whilst I was posting. :D
 

themole

tramways
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Often, there was a skate on the overhead, that was actuated by the trolley head, or pantograph, as it passed through. This then controlled the tram signal. Alyn
 

tramcar trev

all manner of mechanical apparatus...
themole said:
Often, there was a skate on the overhead, that was actuated by the trolley head, or pantograph, as it passed through. This then controlled the tram signal. Alyn
Yes, how quickly we forget.... I remember seeing the contacts and wondered what they were for, and was told after I asked....
Thanks guys for the solution, this will work in the interim while I'm using track polarity to control direction.....
 

tramcar trev

all manner of mechanical apparatus...

tramcar trev

all manner of mechanical apparatus...
Some pics of the real thing from the Brisbane tramway museum.....
I have made mine using the single light version, the mould has been made and the first copy produced eith a red/green led encapsulated but it was not a resounding sucsess..... Has anyone ever machined the domed end of an LED and created a fresnel lens in minature????

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tramcar trev

all manner of mechanical apparatus...
Here it is.... the circus diagram to end all circus diagrams.... even a "how this all works" dialougue.... OK so all you electronics whiz kids can you tell me if it is worth making up a Vero Board prototype?

Model Tramway Signalling System
Simple Block Module
Inputs
Reed switches connected to the inputs must be capable of carrying 600 microAmps. They are held HI by resistors and connect to the 0 volt rail. The switches are operated by magnets on the vehicles.
Inputs may also be driven by CMOS gates.
Outputs
LED outputs are intended to drive two Red/Green common cathode LEDs. Output current is 20 milliAmps to each LED.
Relay contacts are normally open. The contacts are closed when the circuit is reset.
Operation
All inputs are pulled high by resistors and are activated by normally open reed switches connected to the 0 volts rail. The reed switches are operated by magnets on the vehicles.
The RST (reset) input is also held high and is connected to the 0 volt rail to reset the module. When the module is reset, the relay is operated, the relay contacts are closed and LED1 and LED2 outputs are HI (LEDs light).
When a magnet is brought into proximity of the reed switch connected to a1, the a1 input goes LO, the output relay is released thus opening the output contacts. LED1 and LED2 outputs go LO extinguishing these LEDs, LED3 and LED4 go HI.
The output remains in this condition when the a1 reed switch is released and the a1 input returns to HI.
When a magnet is brought into proximity of the reed switch connected to a2, the a2 input goes LO, the output relay is operated thus closing the output contacts restoring the circuit to reset condition.
The output remains in this condition when the a2 reed switch is released and the a2 input returns to HI.
Dual Bidirectional Addon
The Dual Bidirectional Addon combines with two Simple Block Modules to control traffic in a bidirectional section of track.
Inputs
Reed switches connect to the inputs a11, a12, a13, b11, b12, b13 and RST
Outputs
The outputs from the module connect to two simple block modules a and b controlling traffic in the A and B directions respectively. The output RST connects to both Simple Block Modules.
Operation
RST performs the normal reset function on both Simple Block Modules as described above.
When the input reed switch a11 or b11 is operated, outputs a11 and b11 go LO, releasing the relays in both Simple Block Modules, removing power from track sections in both directions thus preventing a rear end collision from following traffic and head on collision with traffic in the other direction.
Reed switches a13 and b13 are placed to detect traffic that enters the unpowered sections of track while traffic traverses the bidirectional section. When the reed switch is closed, the presence of a vehicle is recorded and stored in a latch. The latch remains operated when the reed switch opens again.
A vehicle travelling in the A direction will operate reed switch a11 on entry to the bidirectional section and a12 on exit. A vehicle travelling in the B direction will operate switches b11 and b12.
When a vehicle exits the bidirectional section, the Module checks to see if any vehicles are waiting and reacts as follows:
Vehicle travelling in A direction
No vehicles waiting
Modules A and B reset

Vehicle waiting in A direction
Modules A and B reset

Vehicle waiting in B direction
Module B reset

Vehicles waiting in A & B direction
Module B reset
Vehicle travelling in B direction
No vehicles waiting
Modules A and B reset

Vehicle waiting in A direction
Module A reset

Vehicle waiting in B direction
Modules A and B reset

Vehicles waiting in A & B direction
Module A reset

Thus in heavy traffic conditions, traffic will traverse the bidirectional section alternately in each direction.
The traffic waiting latches a13 and b13 are reset by switches a11 and b11 respectively when the waiting vehicles move off.


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tramcar trev

all manner of mechanical apparatus...
Updated progress.... Well after much "research" I chose a nice olde worlde staff box to model, as made by Duncan & Fraser of Adelaide SA untill around 1930. has a large bi coloured front light with a smaller safety repeater on the side. Much conjecture as to the real purpose of the saftey repeater but popular opinion would suggest that in some places the tram actally stopped beside the staff which was mounted on either a centre pole or on a pole at the roadside with a bundy clock on it so the reapeater just showed that it was ok to proceed even though the driver facing the red light could visuually see the approaching tram move off the single track. A lot of fun to make but they will "dazzle em with detail" to keep the rivet counters appropriatley occupied so they don't get a chance to count the spokes in the tram wheels etc....
So here it is in pictures... the brass thing with the crosshatched top is to encapsulate the reed switches and will sit between the tracks ( the rivet counters will try to pry the lid off). I used a 5mm led for the main light and 3mm for the repeater. All controlled by a very simple circuit made up on vero board and activated by magnets under the trams tripping the reed switches.
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