railroad crossing sign

[lionelsoni]

Here's a stab I took years ago at the simplest possible electronic flasher. I tacked one together; and it seemed to work fine. I don't have any way to show you a schematic; but I'll try to describe the circuit. I will put Radio Shack stock numbers and prices in parentheses.

Get a bridge rectifier (276-1152, $1.49). Connect one of the two terminals on each side of the "+" marking to the accessory voltage of the transformer or to the center rail of the track. Connect the rectifier terminal on the other side of the "+" to an insulated running rail.

Connect the "+" terminal of the rectifier to the positive terminal of a 1000-microfarad capacitor (272-1019, 2 for $1.69, or 272-1047, 2 for $2.59) and the rectifier terminal opposite the "+" to the negative terminal of the capacitor. Call the positive capacitor terminal V+ and the negative V- from here on.

Connect the crossing-signal common, terminal 1, to V+. Connect the emitters, marked "E", of two 2N3904 transistors (276-2016, $.69) to V-. Connect one crossing-signal lamp, terminal 2, to the collector, marked "C" of one transistor, the other lamp, terminal 3, to the collector of the other transistor.

Connect a 3300-ohm resistor (271-1122, 5 for $.99) between V+ and the base, marked "B", of one transistor. Do the same with another resistor for the other transistor. Connect the positive terminal of another 1000-microfarad capacitor (272-1019, 2 for $1.69, or 272-1047, 2 for $2.59) to the collector of one transistor and the negative terminal to the base of the other transistor. Then do the same, switching the roles of the two transistors.

If the circuit flashes too slowly for you, decrease the capacitance of the last two capacitors described; increase capacitance to slow it down. An easy way to cut the speed in half is to put another 1000-microfarad capacitor in parallel with each of the existing capacitors.

[eZAK]

Here is how to wire the 760 highway flasher originaly;

http://www.portlines.com/portlinesclinic28.htm

Flasher source;

http://www.dallee.com/Flasher.html or http://www.dallee.com/FlasherDT.htm

If you want to build your own circuit;

http://members.cox.net/ndoerry/train/CrossingBlinkerMod.pdf

[bfskinner]

mstruro,

1. Both "Burns Manufacturing" and "Depotronics" (among others) have offered electronic flasher circuits in the past. Don't know what is available today.

2. Don't know what bulbs your device requires but "flasher bulbs" are available in some sizes and can be dyed red if necessary. With these you would need only detect the presence of a train at the crossing, which you could do semi-reliably with a Lionel 153 contactor which uses the weight of the cars passing over it to detect the train.

3. Lionel made a special flash-producing contactor known as the 154C for its early model 154 flashing crossing signal, which may work similarly to yours. (Ebay has a set at auction right now.) The design is simple and reliable, but the lamps do not flash very evenly, as the principal involves using the wheels as actuators. You get a kind of blink blink -- pause -- blink blink as the front and rear trucks of each car pass over the contactor. Not too impressive if the train is crawling, but it looks better "at speed." For many years this was about all there was, and I still use them on my postwar layout.

As lionelsoni has said, to get "prototypical" operation you will probably have to use a modern electronic device.

[lionelsoni]

Mike sent me this by e-mail:

"thanks for the help on the railroad sign. the sign is wired, two wires are comming down the inside and running to the two outside posts underneth the sign. the post in the middle does not have a inside wire on it . I hooked the two wire posts to a transformer and both bulbs lite up what I dont know is how this hooks to the track so when the train comes the lights come on or bilnk, is their some connection that goes on the track and then to the transformer? and what is the center post on the sign for?thanks Mike."

The center post is the common terminal.  One way to wire up this kind of signal is to create two "control rails", which are insulated sections of the outside rail of the track.  Connect each control rail to one of the outside terminals.  Connect the center terminal to the center rail of the track or to an accessory voltage which has a common return with the track supply.  As the train's wheels roll across each control rail, the corresponding light will come on.  The trick is to locate the control rails so that the two lights flash alternately.  You will probably have to settle for an uneven flashing behavior.

To get even flashing, you will probably have to use some electronics.  I would build my own; but you may be able to find someone selling a ready-made circuit for this.  Does anyone have a suggestion?

You could perhaps use a Lionel 153C contactor, which is a single-pole-double-throw switch that goes under the track and is activated by the weight of the train.  However you would want to shut the thing off when the train is not present, which could be done with a single long control rail centered on the contactor.

[lionelsoni]

If as you say it's old, it's very unlikely that there is anything in it but the two lamps.  So set your transformer to about 12 volts and connect it to two of the three terminals.  There are only three ways to do this.  The three things that should happen are that one light should light, that the other light should light, and that both lights should light together but dimly.

[eZAK]

Any Pics?

Is it metal with a cast base? (Cross bucks, 2 red lights w/screw base bulbs, square post all on a large base)

If so, it could be an Am. Flyer piece.

[Anonymous]

    Can anyone help? I have a old toy railroad crossing sign, the only markings on it is made in

   usa. could be an old marx.  there is no gate it is just the railroad crossing sign with flashing lights

.  I don't know how to hook it up to  see if it works.  there are three wire posts in the back but I don't know what to connect them to any help would be great thanks!