Marcway Points, and wiring them for DCC.

[250BOB]

I use Peco code 75 electrofrog, and thats my knowledge base....however, over Christmas a friend building his first ever layout using Marcway points, has asked me to come over and help him lay his first track and points, using a gaugemaster dcc prodigy as his controller.

Its the points that I have no knowledge about, unlike Peco code 75 electrofrog points, the Marcway have no wiring.??????

Anybody care to point me in the right direction please.??

Thanks.......................Bob

[gordon s]

Are they PCB soldered Bob or made on plastic bases?

 

Essentially they are much the same as most points. One feed to each stock rail as a start. You then need to check the frog is isolated from the switch rails. If the frog is completely isolated, then that can be fed via a microswitch to provide the correct polarity. You may also want to check the switch rails are bonded to the adjacent stock rail. If it is PCB assembly, connection should already be there via the PCB sleepers.

 

This may help.....

 

 

[Kenton]

As always no different than for DC

otherwise just as stated by Gordon with that nice image that explains it all.

[250BOB]

Thanks guys....I'll check out if they are pcb or plastic sleepers and get back.

 

Looks to be not too difficult then.!!!

 

Bob

[gordon s]

Found this pic I must have done a while back to show the polarity issues...

 

[250BOB]

Thanks Gordon.

But if you choose not to put the gaps in the switch rails, does the frog become live depending on which way the turnout is set.?

What problems will you have if you do this.?

Bob

[beast66606]

Thanks Gordon.

But if you choose not to put the gaps in the switch rails, does the frog become live depending on which way the turnout is set.?

What problems will you have if you do this.?

Bob

 

Think about it Bob, if both switch rails are continuous to the frog ... dead short

[Kenton]

You could put more cuts in the sleepers of this type of point to isolate the switch rails - but I really would not recommend that.

[250BOB]

Think about it Bob, if both switch rails are continuous to the frog ... dead short

 

Of course, what am I like, , it shorts back thro the sleepers....completely.!!!!

Thanks Dave

[naugytrax]

if you choose not to put the gaps in the switch rails, does the frog become live depending on which way the turnout is set.?

 

Yes, if your Marcway points are like mine which I bought last year. The images posted above seem to be of Scaleway or some other different brand, unless Marcway have changed their design recently.

On my Marcways, there is no need to cut additional insulation between the switch rails and the stock rails since the sleepers are already gapped here. If you cut gaps in the switch rails to isolate them from the crossing, you will need to supply extra feeds to the switch rails. My Marcway points are wired exacly like Peco Electrofrogs, but of course my information may be out of date.

[gordon s]

The problem with that type of construction is that feeding the switch rails through the crossing will mean that one of the switch blades will be at the opposite polarity to the adjacent stock rail. Any wheel which then has a tight B2B or wider tread may cause a short as it bridges across the gap between the two rails. Certainly not ideal for DCC operation where a momentary short will shut down the system.

 

Personally I prefer the wiring I have shown with the switch rails bonded to the adjacent stock rail.

 

You are right though. Those are not Marcway, but my own PCB construction simply used as a generic example.

[250BOB]

Yes, if your Marcway points are like mine which I bought last year. The images posted above seem to be of Scaleway or some other different brand, unless Marcway have changed their design recently.

On my Marcways, there is no need to cut additional insulation between the switch rails and the stock rails since the sleepers are already gapped here. If you cut gaps in the switch rails to isolate them from the crossing, you will need to supply extra feeds to the switch rails. My Marcway points are wired exacly like Peco Electrofrogs, but of course my information may be out of date.

 

Ahhh.......I dont have these points here, they belong to a pal of mine who is building his first layout, so I cant examine them closely until next week. Interesting to learn that the Marcway points are wired like the code 75 peco ones.

Also, I know what you mean Gordon...but to get the guy going, I will not wire up initially, and when he gets the shorts from wheels touching both stock and switch rail, he may well then decide to do the rest. I will give him the options.

Thanks for your help everyone.

Bob.

[Kenton]

but to get the guy going, I will not wire up initially, and when he gets the shorts from wheels touching both stock and switch rail, he may well then decide to do the rest. I will give him the options.

No don't do that! show and insist on the right way to wire a point from the beginning - that way he will not be back a couple of months from now asking why it doesn't work. There is only one way - the right way.

[250BOB]

No don't do that! show and insist on the right way to wire a point from the beginning - that way he will not be back a couple of months from now asking why it doesn't work. There is only one way - the right way.

 

Yes.......I know you're right really, its better to bite the bullet earlier than later, it will become a bigger job to do it retrospectively.

 

Thanks for all your input Kenton.

 

Bob

[bigdaveadams1]

Here's a question from a copper clad novice.....what's the best tool for scoring through the copper clad as per the suggestions? Craft knife do?

[philsandy]

I used a small square file. You only need to remove the thin copper clad, so about 0.25 mm deep, if that,  is all you need to go. Then hide the filed groove with paint, eg. Sleeper Grime.

[bigdaveadams1]

Cheers. I've got a square file, so I'll get onto them with that.

[250BOB]

No don't do that! show and insist on the right way to wire a point from the beginning - that way he will not be back a couple of months from now asking why it doesn't work. There is only one way - the right way.

Hi Kenton,

6 to 7 years later, and does he regret it now...!!!!

Continually having to clean the contact between switch and stock rail........we were warned..!!!

Backs to back shorts pretty well eliminated by adjustments of all locos and stock, but the electrical continuity is awful.

Bob

[hayfield]

There should be no issues with electrical continuity with copperclad turnouts and crossings. The way Marcway (and I guess some builders) decide to both hide the isolation cuts plus make the wiring easier does throw up a potential problem of electrical continuity which in the end can be easily resolved

 

If using a point motor use the accessory switch to change polarity if it has one. If it does not or some form or wire in the tube method is being used then a micro switch can be made to activate when the switch is changed.

 

Finally if these are not an option a very low tech method which is the reverse of the SMP method.

 

The sleeper before the tiebar either has to be changed or altered so that there is an isolation gap dead centre (if using the old sleeper bridge the original isolation gaps)

On the tiebar solder a brass or steel wire so it goes over the new/altered sleeper

On the new / altered sleeper both sides of the isolation gap drill a small hole and solder a piece of wire in it and trim to about 1 mm high

 

You now have a switch built into a turnout which can be hidden by one of those ramps which protect the point locking system

[250BOB]

There should be no issues with electrical continuity with copperclad turnouts and crossings. The way Marcway (and I guess some builders) decide to both hide the isolation cuts plus make the wiring easier does throw up a potential problem of electrical continuity which in the end can be easily resolved

 

If using a point motor use the accessory switch to change polarity if it has one. If it does not or some form or wire in the tube method is being used then a micro switch can be made to activate when the switch is changed.

 

Finally if these are not an option a very low tech method which is the reverse of the SMP method.

 

The sleeper before the tiebar either has to be changed or altered so that there is an isolation gap dead centre (if using the old sleeper bridge the original isolation gaps)

On the tiebar solder a brass or steel wire so it goes over the new/altered sleeper

On the new / altered sleeper both sides of the isolation gap drill a small hole and solder a piece of wire in it and trim to about 1 mm high

 

You now have a switch built into a turnout which can be hidden by one of those ramps which protect the point locking system

The points were laid as bought, using the little black plastic point levers to change direction with them. There are no point motors, no tubes in wire etc., and there is not going to be, as the layout track is too permanent now.

Personally, I would lift all the points and start again by making the amendments to the points.... but its not my layout.

Thanks for your advice, sounds interesting.

Bob.

[hayfield]

Bob

 

The simple modification (with the wires) I have suggested would be simple to do with the points in situ and not take all that long to do

[clecklewyke]

Has anyone any experience of using rtr Marcway three-way points?

 

I know how to wire normally constructed points but rtr Marcway are unusual in that the two switch blades for any turnout are wiried together and bonded to the frog.

 

This has advantages in that there is no need for any additional wiring of a simple turnout but it has the following disadvantages:

 

1) electrical continuity is dependent on contact between the switch blade and the adjacent stock rail.

 

2) since both switch rails are bonded to each other, if the back of a flange touches the back of the opened switch blade it will cause a short. As someone above has pointed out this can be resolved by carefully adjusting back to backs, checking gauges and having a wider than desirable gap between switch blades and stock rails.

 

I am prepared for the moment to accept these disadvantages because as they come they need no microswitches, accessory switches or wiring, which means I can get things running quickly, although I will probably ultimately wire them like normally-constructed turnouts, with the switches gapped from each other and the frog and bonded to their adjacent stock rail. That will take time and is a long way down the project plan. Signals will come first!

 

So, with these caveats it all works fine now except for the three-way point. This has a length of rail between the two frogs which is never live, even though the appropriate switch blades are in electrical contact with their stock rails.

 

I could overcome that by putting in a microswitch to feed the frog but that goes against the simplicity of the point as it comes from Marcway. Have I missed summat?

 

Ian

 

(Incidentally, many of the posts above, including the diagrams of example points, do not relate to rtr Marcway points. They do relate to Scaleway and the normal method of construction of hand-built points but NOT to Marcway, so please do not muddy the water with irrelevant information!

[hayfield]

If the wiring of the Marcway turnouts cause problems with the voltage used by DCC and the way in which the system uses the (live) wired switch blade assemblies then you might need to alter the electrical isolation method to a more conventional system. This would involve using switches for the common crossing polarity.

 

C&L wiring diagram

http://www.finescale.org.uk/pdfs/3way.pdf

 

You would need to cut isolation gaps on the sleepers and add a few bonding wires etc