Wiring a Lionel 154 Railroad Crossing Flasher

[lionelsoni]

Here's my stab at the simplest possible electronic flasher. I just tacked one together; and it seems 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 in parentheses.

Get a bridge rectifier (276-1152). 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 (272-958) 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) 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 (271-1328) 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 (272-958) 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 two more 1000-microfarad capacitors each in parallel with one of the existing capacitors.

The parts cost, according to my 2002 catalog, is about $6.

Bob Nelson

[tmackinator]

The timer chip is available at any radio shack or any electronic parts house.
http://www.mrollins.com/flash3.html This is one link for circuits
http://home.cogeco.ca/~rpaisley4/PwrFlasher.html This is the circuit I built. I used the original circuit using the 555 chip. I also used transistors suitable for incandescent bulbs, not led's. you also have to build a power supply circuit to rectify your ac to dc unless you have a dc source. hope this helps, have fun-tm

[tmackinator]

The timer chip is available at any radio shack or any electronic parts house.
http://www.mrollins.com/flash3.html This is one link for circuits
http://home.cogeco.ca/~rpaisley4/PwrFlasher.html This is the circuit I built. I used the original circuit using the 555 chip. I also used transistors suitable for incandescent bulbs, not led's. you also have to build a power supply circuit to rectify your ac to dc unless you have a dc source. hope this helps, have fun-tm

[lionelsoni]

You might check out http://www.grahamstrains.com/index.html . He has flashers for $18. The listing says "sold", but the description implies that he stocks them in quantity.

Bob Nelson

[lionelsoni]

You might check out http://www.grahamstrains.com/index.html . He has flashers for $18. The listing says "sold", but the description implies that he stocks them in quantity.

Bob Nelson

[Anonymous]

tmackinator,
Where did you get that 555 timer chip you referred to? Is it available at Radio Shack? Do you have a schematic or could you provide some information on how you wired it?

Thanks

[Anonymous]

tmackinator,
Where did you get that 555 timer chip you referred to? Is it available at Radio Shack? Do you have a schematic or could you provide some information on how you wired it?

Thanks

[tmackinator]

Thanks for the correction. terminal 1 is indeed ground so tie 2&3 together and feed with power, terminal one goes to the insulated rail. The flasher circuits either built or bought give the most realism with the most reliability. Usually you can build them for under $10 with parts available at any radio shack. sorry for the brain fade.

[tmackinator]

Thanks for the correction. terminal 1 is indeed ground so tie 2&3 together and feed with power, terminal one goes to the insulated rail. The flasher circuits either built or bought give the most realism with the most reliability. Usually you can build them for under $10 with parts available at any radio shack. sorry for the brain fade.

[lionelsoni]

Actually, terminal 1 is ground.
I have an idea for you, but I must warn you that I have not tried it out:
Create an insulated rail for the distance that you want the flasher to respond to. But separate a short section, perhaps at one end, so that you actually have two consectuive insulated rails, one long and one short. Connect the long insulated rail to one of the lamps, say at terminal 2. Connect the short insulated rail to terminal 1, which will no longer be used as a ground terminal. Connect the supply voltage, either an accessory voltage from the transformer or the center rail, to the other lamp, terminal 3. Now, between terminals 1 and 3 connect another several lamps of the same size as in the signal.
The way it works is that, when the wheels ground the long insulated rail, current flows through both lamps in series, but one glows dimly if at all because most of its current is shunted by the auxiliary lamps. But when the wheels ground the short insulated rail, the shunted lamp receives the full voltage and lights brightly, while the unshunted lamp is shorted out. The auxiliary lamps will light brightly too, so locate them where they cannot be seen, perhaps under the layout.
The tricky part is deciding on the length of the short insulated rail. It should be long enough so that two coupled trucks of adjacent cars keep it grounded but short enough that it can be completely between the two trucks of one car. If you run mostly freights or mostly passenger trains, you can probably easily find a good length. If it has to work with both, you will have to compromise, with uneven flashing as the result.

[lionelsoni]

Actually, terminal 1 is ground.
I have an idea for you, but I must warn you that I have not tried it out:
Create an insulated rail for the distance that you want the flasher to respond to. But separate a short section, perhaps at one end, so that you actually have two consectuive insulated rails, one long and one short. Connect the long insulated rail to one of the lamps, say at terminal 2. Connect the short insulated rail to terminal 1, which will no longer be used as a ground terminal. Connect the supply voltage, either an accessory voltage from the transformer or the center rail, to the other lamp, terminal 3. Now, between terminals 1 and 3 connect another several lamps of the same size as in the signal.
The way it works is that, when the wheels ground the long insulated rail, current flows through both lamps in series, but one glows dimly if at all because most of its current is shunted by the auxiliary lamps. But when the wheels ground the short insulated rail, the shunted lamp receives the full voltage and lights brightly, while the unshunted lamp is shorted out. The auxiliary lamps will light brightly too, so locate them where they cannot be seen, perhaps under the layout.
The tricky part is deciding on the length of the short insulated rail. It should be long enough so that two coupled trucks of adjacent cars keep it grounded but short enough that it can be completely between the two trucks of one car. If you run mostly freights or mostly passenger trains, you can probably easily find a good length. If it has to work with both, you will have to compromise, with uneven flashing as the result.

[tmackinator]

Since the middle post is a ground and the outer posts go to each light respectively, tie the two outer posts together and feed with the hot side of your power source. Connect the negitive side to the insulated rail and the flasher will illuminate. ( both lights on continuously) when the train rolls over. I built a flasher circuit using a 555 timer chip which is activated by the insulated rail. This causes the lights to alternatly blink and the rate is adjustable. This and many other circuits are readily available on the net by searching model railroad electrical circuits or there are some ready made flasher circuits for this application. Make sure you choose one that will be suitable for incandescent bulbs and not led's. There is also a couple of books available on all typs of model railroad circuits. Good luck and have fun-tm

[tmackinator]

Since the middle post is a ground and the outer posts go to each light respectively, tie the two outer posts together and feed with the hot side of your power source. Connect the negitive side to the insulated rail and the flasher will illuminate. ( both lights on continuously) when the train rolls over. I built a flasher circuit using a 555 timer chip which is activated by the insulated rail. This causes the lights to alternatly blink and the rate is adjustable. This and many other circuits are readily available on the net by searching model railroad electrical circuits or there are some ready made flasher circuits for this application. Make sure you choose one that will be suitable for incandescent bulbs and not led's. There is also a couple of books available on all typs of model railroad circuits. Good luck and have fun-tm

[Anonymous]

I have a Lionel #154 Railroad Crossing Flasher with 3 wiring posts. I would like to activate this using an insulated rail instead of a 153 contactor. Does anyone know of a way to do this inxepensively?

Thanks

[Anonymous]

I have a Lionel #154 Railroad Crossing Flasher with 3 wiring posts. I would like to activate this using an insulated rail instead of a 153 contactor. Does anyone know of a way to do this inxepensively?

Thanks