Cromford Wharf Shunting layout - structures and scenery

[Enterprisingwestern]

Hi Michael, yes, that's right, the live feed from the CDU goes to the central terminal on the switch, and the two coils (normal and reversed) of the point motor come off the outer terminals. The toggle switch is non-latching, so is sprung to return to the centre (off) position when released.

 

Al.

 

Pardon my dimness, but what is the advantage of this over a, say, stud and probe system with 2 led's and resistors from the point microswitch?

 

Mike.

[Alister_G]

Pardon my dimness, but what is the advantage of this over a, say, stud and probe system with 2 led's and resistors from the point microswitch?

 

Mike.

 

It just saves a bit of wire, really, that's all.

 

It means that the LEDs and the controlling logic are all on the control board, instead of running wires to feed the LEDs to and from every point. The only wires to the point, doing it this way, are the two feeds to the motor, normal and reversed.

 

The other thing is, the point and the LEDs will never be out of sync, and it saves the last state of the point when power is removed.

 

Al.

[Alister_G]

A slight refinement of technique, tonight.

 

The first pair of LEDs were wired up with the resistors soldered to the individual common return legs of the LEDs:

 

 

This was a bit fiddly, and a bit messy, so for the second set of LEDs on the next point, I tried something different.

 

I took a small piece of stripboard or veroboard with 5 tracks on it. The second track, which corresponds to the common return lead on the LED, I cut away the copper between the two LEDs.

 

 

Each side of the cut I then added the resistor, linking between track 2 and track 5

 

 

The wires were soldered to track 1 and track 3 for the two feeds, and the common return to track 5, and then the LED legs were soldered to tracks 1, 2 and 3, either side of the resistors.

 

 

This looks much neater, to my mind.

 

So, the second turnout now has it's position indicators.

 

With the turnout normal, (switch down) traffic goes on the main line towards the incline:

 

 

and with the turnout reversed, (switch up) traffic is routed to the siding:

 

 

That's all for now,

 

Al.

[Stubby47]

You could add the resistors to the circuit next to the relays - a single pcb board with a row of resistors would look neat and keep the wires at the LEDS simpler.

[mjcampbell]

I'd not thought of using a 2-pole non-latching switch to set a relay as well as throwing the solenoid. Makes a lot of sense. 

 

For our club layout I'm experimenting with bi-stable latching relays - for a slightly different purpose with different point motors - but I expect that's what these circuits use. A pulse to one coil sets the contacts one way, a pulse to the other sets them the other way, and as they latch a short pulse is all they need. It wouldn't be hard to make your own circuits with them and incorporate the LED's. If you're interested the relays I'm using are these. 

 

Pardon my dimness, but what is the advantage of this over a, say, stud and probe system with 2 led's and resistors from the point microswitch?

 

Mike.

 

I always use the point motor switch to switch the point frog - I use live frog points and small rail section. So a separate circuit for LED's makes sense.

 

A thought on stud contact - why not replace the studs with push-buttons? It saves having to find the dangly bit of wire when you need it!

[Alister_G]

You could add the resistors to the circuit next to the relays - a single pcb board with a row of resistors would look neat and keep the wires at the LEDS simpler.

 

Hi Stu,

 

Thanks for the suggestion, I did actually consider doing that first, but I decided against it, primarily because of the lack of space for the PCB, and also (completely irrationally) it would mean running an extra wire from the LEDs back to the board, which I didn't want to do.

 

For a future build - say when I do Grindleford, I will bear it in mind and actually plan it out prior to starting

 

Cheers,

 

Al.

[Enterprisingwestern]

It just saves a bit of wire, really, that's all.

 

It means that the LEDs and the controlling logic are all on the control board, instead of running wires to feed the LEDs to and from every point. The only wires to the point, doing it this way, are the two feeds to the motor, normal and reversed.

 

The other thing is, the point and the LEDs will never be out of sync, and it saves the last state of the point when power is removed.

 

Al.

 

But, if the point motor doesn't throw correctly, how is that indicated?

 

Mike.

[Alister_G]

I'd not thought of using a 2-pole non-latching switch to set a relay as well as throwing the solenoid. Makes a lot of sense. 

 

For our club layout I'm experimenting with bi-stable latching relays - for a slightly different purpose with different point motors - but I expect that's what these circuits use. A pulse to one coil sets the contacts one way, a pulse to the other sets them the other way, and as they latch a short pulse is all they need. It wouldn't be hard to make your own circuits with them and incorporate the LED's. If you're interested the relays I'm using are these. 

 

 

I always use the point motor switch to switch the point frog - I use live frog points and small rail section. So a separate circuit for LED's makes sense.

 

A thought on stud contact - why not replace the studs with push-buttons? It saves having to find the dangly bit of wire when you need it!

 

Hi Michael,

 

Yes, the module is basically just a bi-stable latching relay with screw terminals and a power LED. They do look to be the same type of relay as you link to.

 

The attraction of buying the module is simply that it works out cheaper than to buy the individual components and put it together myself, however it does then limit me to using off-board resistors and LEDs.

 

Al.

[Stubby47]

If the resistors are wired to the LED common return, would one larger resistor in the commom return work as well ?

[Alister_G]

But, if the point motor doesn't throw correctly, how is that indicated?

 

Mike.

 

Um, the train crashes?

 

True, you lose that indication.

 

However, my primary goal on this occasion is to limit the connections required between the control board and the layout, however irrational that may be, and therefore this solution works for me.

 

To pick up on the point (sorry) made by Michael above, do you also switch the frogs when using your method? And if so, does that mean you have extra switch contacts at each turnout?

 

Al.

[Alister_G]

If the resistors are wired to the LED common return, would one larger resistor in the commom return work as well ?

 

I would have thought in theory it would, but I also have a nagging doubt in the back of my mind that there is a reason that you normally see individual resistors for each LED, instead of commoning all the cathodes together and then having one big resistor.

 

I've forgotten nearly all of my electronic theory nowadays, but I believe it is because although when you buy a pack of LEDs they should nominally all have the same characteristics, in practice this is not necessarily the case, and one may draw considerably more current than the others.

 

With a single current limiting resistor on parallel LEDs, this would mean that one LED would be much brighter than the others, as it would draw more of the current through the resistor.

 

Al.

[Enterprisingwestern]

 

 

To pick up on the point (sorry) made by Michael above, do you also switch the frogs when using your method? And if so, does that mean you have extra switch contacts at each turnout?

 

 

 

A standard microswitch with common/NC/NO connections suffices, positive and negatives from a dedicated circuit under the layout.

 

Mike.

[Andrew P]

I would have thought in theory it would, but I also have a nagging doubt in the back of my mind that there is a reason that you normally see individual resistors for each LED, instead of commoning all the cathodes together and then having one big resistor.

 

I've forgotten nearly all of my electronic theory nowadays, but I believe it is because although when you buy a pack of LEDs they should nominally all have the same characteristics, in practice this is not necessarily the case, and one may draw considerably more current than the others.

 

With a single current limiting resistor on parallel LEDs, this would mean that one LED would be much brighter than the others, as it would draw more of the current through the resistor.

 

Al.

Vooooooooom wshhhhhhhhhhhhhhhh  way over my head, all that Electrikery stuff Al,    but at least YOU know what your doing and it looks really good mate.

[Alister_G]

Vooooooooom wshhhhhhhhhhhhhhhh  way over my head, all that Electrikery stuff Al,    but at least YOU know what your doing and it looks really good mate.

 

Cheers matey, I'm straining the limits of my knowledge here, but at least it sounds convincing :D

 

Al.

[Enterprisingwestern]

Cheers matey, I'm straining the limits of my knowledge here, but at least it sounds convincing :D

 

Al.

 

Me too, if you can't blind 'em with science, baffle 'em with bullsh!t!

 

Mike.

[mjcampbell]

I would have thought in theory it would, but I also have a nagging doubt in the back of my mind that there is a reason that you normally see individual resistors for each LED, instead of commoning all the cathodes together and then having one big resistor.

 

I've forgotten nearly all of my electronic theory nowadays, but I believe it is because although when you buy a pack of LEDs they should nominally all have the same characteristics, in practice this is not necessarily the case, and one may draw considerably more current than the others.

 

With a single current limiting resistor on parallel LEDs, this would mean that one LED would be much brighter than the others, as it would draw more of the current through the resistor.

 

Al.

 

That's correct - or at least, I've been told the same thing by someone who would know for sure!

 

The bi-colour LED's can have different current consumption for red and for green, so for some LED's you may even need a different resistor for each leg. 

[stevejjjexcov]

Enjoyed reading about your exploits with elcktricery. I still don't understand what's going on but it looks great! I did wire a layout once using the principle feed everything and get ride of what you don't need. It worked ok......just,there were only 4 turnouts though

All the best Steve

[Alister_G]

A quick update.

 

The control panel is now completely wired, and now just needs connecting to the wiring on the baseboard:

 

 

I need some time to fit and connect the point motors, but not sure if this will be done now before I go away on holiday.

 

In other news, I've been continuing with the workshop buildings, and those done so far have been painted:

 

 

 

 

 

 

 

As you can see the roofs are on, but need the slates adding.

 

Thanks for looking,

 

Al.

[Signaller69]

The buildings look excellent Al, suitably grubby weathering looks great.

 

Martyn.

[Andrew P]

All looking very good Al, I'm looking  to the Flockery bits now.        

[Alister_G]

All looking very good Al, I'm looking  to the Flockery bits now.        

 

I'm afraid the flockage won't begin until after my holiday, probably, but hopefully we should see trains running in June.

 

Al.

[MarshLane]

Hi Al,

Wow your thundering on with this! The buildings look great! Had a trip out to High Peak last weekend, so if you need/want any detail shots of the buildings let me know.

 

Rich

[Alister_G]

Hi Al,

Wow your thundering on with this! The buildings look great! Had a trip out to High Peak last weekend, so if you need/want any detail shots of the buildings let me know.

 

Rich

 

 

Hi Rich,

 

Thanks very much, would love to see some of your photos, if you want to post them on here?

 

Al.

[vulcan product fan]

Great work as always Al a local mag did a feature on the high peak railway very recently and my dad wants to go up and have a look arounds so may visit cromford very soon 

[bescotbeast]

A quick update.

 

The control panel is now completely wired, and now just needs connecting to the wiring on the baseboard:

 

wiring-cromford021.jpg

 

I need some time to fit and connect the point motors, but not sure if this will be done now before I go away on holiday.

 

In other news, I've been continuing with the workshop buildings, and those done so far have been painted:

 

the-cromford-build083.jpg

 

the-cromford-build084.jpg

 

the-cromford-build085.jpg

 

the-cromford-build086.jpg

 

the-cromford-build087.jpg

 

the-cromford-build088.jpg

 

As you can see the roofs are on, but need the slates adding.

 

Thanks for looking,

 

Al.

Grimey stonework to model and you're as happy as a pig in muck Al