This is the most difficult project on this site. It takes a lot of work but it is worth it. This project shows you how to make a working railway crossing which is activated by the train, making the amber light come on first followed by the flashing red lights. The train then cancels the lights.

Click here to see it in action (Movie) (4mb)

Model Railway Crossing

Railway Crossing Barrier

Model Railway Crossing

1. All the shapes (A to D) can be cut out of 1mm - 0.5mm card. For part A it might be best to print them onto photo card and then stick them onto thicker card. The other option is to paint on the detail.

3. The tabs at the bottom of part C are to hold up the barrier when it is installed on your layout. It will require two small holes in your baseboard.

4. Make a small hole in all the parts. Use a small piece of paperclip and thread it through. This will act as a hinge. To stop it from falling out, you can bend over the ends with pliers. This is not the easiest thing to do.

Railway Crossing Sign

Model Railway Crossing Sign

Save this image and then print it onto glossy photo card.

1. To take the 3mm LED's you will need to make 3 X 3mm holes in the card where the lights will be pushed through.

Tread the wires through a thin straw, they will require some bending to bring them in to the middle.

2. The back of the strip board will be very bumpy from the soldering. I used a glue gun to put a layer of glue over the strip board and before it cooled I flattened it and made it square. You could also use Polly Filler to flatten the back. Both methods have the added benefit of permanently fixing the wires in place. Test the lights before you do this task.

3. Paint the light unit a medium grey colour and glue on the printed off sign front.

4. Add some light shads to the lights. Use small pieces of straw cut to the correct shape and painted black.

Model Railway Crossing

Shopping list

Resistors: 680 ×3, 1k ×3, 33k, 47k, 82k, 270k
Capacitors: 0.1µF ×3, 10µF radial ×2
Red LED (3mm best) ×2
Amber LED (3mm best)
555 timer IC ×3
8-pin DIL socket for IC ×3
on/off switch
Battery clip
Reed switch ×2
Miniature magnet - each locomotive needs one
Stripboard

Circuit Diagram

Model Railway Circuit Layout

Enlarge

Stripboard Layout

Model Railway Sripboard Layout

Enlarge

Layout for mounting the LED's (strips going down)

Model Railway Sign Lights

Assembly

For this project step by step instructions would be too long and unhelpful. Instead I have a some advice below. If you haven't got much soldering or electronic experience I would recommend you try one of the simpler projects first like the flashing light or signal.

1. Position the 8-pin DIL socket for the IC (555 timer) first and then work around fitting components to the board in pin order. This will stop you misplacing any of the components or missing them out al together.

2. Only fit the IC (555 Timer) in the 8-pin DIL socket after all the soldering is done. Remember to remove it before making any modification as they are heat sensitive and may be damaged if they are heated by a soldering iron.

IC Chip

3. The X on the strip board indicate holes where the strip needs to be broken. There is a special tool to do this or you can use a drill with a 3mm drill bit. You only need to drill in enough to break the copper strip.

4. You can mount the resisters and the capacitors vertically if they do not fit horizontally. This is slightly weaker but it also reduces the amount of strip board you need. See the picture below:

Component Diagram

5. The trigger and cancel switch can be normal switches or reed switches that can be placed in-between the rail and be activated by a magnet under the train.

6. If at first the circuit does not work, check to see if any solder has crossed to another strip. Also check to make sure that the breaks you made in the strips with the drill have completely severed the copper strip. It only takes a small strand to make a connection and short the circuit.

7. Buy enough parts to build more than one of these circuits as it might take more than one attempt to build this Circuit. I know it did for me.

My Experience

It took me two attempts to build this circuit. It took me over 2 and a half hours to build my first circuit mainly because I was writing the stripboard layout using Mr Hewes circuit diagram. The flashing red light part of this circuit just would not work. So I built the flashing light part separate making sure it worked. I then built the first part of the crossing circuit and attached the out put from pin 3 to the positive terminal of the flashing light circuit and the negative side to the battery. This worked!!! And I was very happy.

Acknowledgement

If you need any additional information The Electronics Club website is a wealth of information and advice.