Peco Code 55 Streamline electrofrog points and DCC

[David Rickard]

Apologies in advance if this is a silly question.

 

I'm using Code-55 electrofrog peco points. I have a feeling I saw something somewhere saying they needed modification to run with DCC. Is that true? I would check the instruction leaflet they came with, only the one copy I carefully kept for reference, I can't find!

 

My reason for asking is that when I originally laid my track, I had used insulating fishplates on the rails connected to the frog. I was planning on using a seperate feed to the frog, switchable when the point switched. As laid, the track seemed fine, but adding the power feed led to a world of shorts and other madness. I've since pulled all that track up and I'm starting again. I'm pretty sure they don't need modification - I'd just like somebody to confirm either way, please!

[Edwin_m]

This one comes up fairly regularly. There are two modifications you might want to do:

 

(1) Connect the frog to a switch which changes with the point, so you are not relying on the contact between the blade and the stock rail to power the frog. This is a good idea as this contact often fails especially if the rails are painted.

 

(2) Isolate the blades from the frog area (eg with a slitting disc) and bond them to the stock rails. This avoids short circuits if the backs of wheels touch the blades.

 

If you do (2) you have to do (1) as well otherwise the frog would always be dead.

 

If you do (1) on its own then in my experience it works fine - the gap between the blades and stock rails on Peco code 55 is so overscale that only a wheelset with back-to-backs grossly out of tolerance will cause a short. Such a wheelset will also cause derailments and needs to be fixed anyway. If anyone recommends (2) then make sure they are speaking from experience with Peco code 55 - it is much more necessary with other track types and in other scales where the gap is less.

 

HOWEVER (1) will only work without (2) if the polarity changes while the blades are in mid-travel. If it switches while the blade is still in contact with either stock rail then the frog area will be connected to both rails at once, which is of course a short circuit. It sounds very much as if this is your problem. I switch the frog via the built-in contact on a SEEP PM1, which works fine in this respect although the switch itself is a bit dodgy. You will get short circuits if there is no mechanical linkage between the polarity switch and the point itself (eg relay powered by point motor drive) and you could also have problems if there is a lot of flex or slop in the mechanical linkage so that the two ends are not precisely synchronised. What arrangement were you using for switching polarity?

 

Hope this makes sense!

[David Rickard]

No that makes sense!

 

I was doing number 1, for exactly the reasons you give. I wasn't going to bother, but consensus seems to be that it's a good idea.

 

I'm using the Heathcoate point indicators, which have a switching relay. I was going to use the PM1 motors originally, but had heard about reliability issues. Instead I got the non-switching variety, and the Heathcoate indicators. I think I just made a right hash of wiring them up.

[Edwin_m]

Sounds like the explanation I posted. The Heathcote device will energise or de-energise its relays immediately the point is commanded to move, and almost certainly the relays will switch faster before the point motor can move the blade away from the stock rail. Result: short circuit, sometimes but not always depending how good the blade contact is.

 

You could perhaps try to slug the Heathcote device with capacitors so it operates more slowly, but I think this would be a lot of hassle to get right (if it is too slow you will have exactly the same problem) and might go wrong again if the points get a bit sticky over time.

 

Other alternatives are to adopt (2) above or to engineer a microswitch on the Seep, possibly operated by the end of the shaft that sticks downwards. Even more elegant would be to lower the Seep on spacers and put the microswitch into the gap between the Seep and the baseboard, but that can't be done once you've cut the Seep actuating shaft to length.

[David Rickard]

I'm sure the Heathcoate devices must work (others use them). I might get in touch with them for some advice. I've yet to lay track, so I'm open to the possibilities right now!

[DavidB-AU]

There is some good advice here: http://www.wiringfordcc.com/switches_peco.htm

 

The principles for Peco electrofrogs are the same for all scales but advice specifically about code 55 is towards the end.

 

Cheers

David

[Edwin_m]

I'm sure the Heathcoate devices must work (others use them). I might get in touch with them for some advice. I've yet to lay track, so I'm open to the possibilities right now!

 

Yes I've no doubt they work as advertised. The problem is that they are expecting you to isolate the frog completely if you plan to use them for frog switching.

[Edwin_m]

There is some good advice here: http://www.wiringfordcc.com/switches_peco.htm

 

The principles for Peco electrofrogs are the same for all scales but advice specifically about code 55 is towards the end.

 

Cheers

David

 

This is my suggestion (2) above. I contend it is not necessary with Peco code 55 unless anyone can say from personal experience with this type of trackwork that they have had a problem with shorts between the switch blade and the stock rail.

 

The advice about a light bulb is also controversial and has been argued over on this forum many times. I don't intend to get involved in that discussion, but if you independently wire the frog then the problem mentioned with "hot spots" shouldn't arise.

[Barry Ten]

I have been using Code 55 with DCC for quite some time and have never encountered any problems. I do apply switched power to the frogs, but that's purely because I find the switch blade contact unreliable, especially (not sure why) with the short radius points I use in the fiddleyard. The longer radius point seem less problematic but I switch them anyway. All I do is solder one wire to the frog, and two to the outer rails. For switching, I use a microswitch glued to the underside of the Peco point motor. Other than that, I don't modify the points in any way.

[RFS]

One reason for doing (2) is if you intend switching frog polarity using a latching relay - either now or at a later date. I've started using these where two points form a crossover, as the relays are DPCO so one can handle both points. The relay board costs about £2.50 to put together (relay, 3-way terminals, piece of stripboard, 3 rectifier diodes) so represents quite a saving compared to 2 PL-13s, which is what I have been using up till now. As the relay switches almost instantly it's important that the frog isn't also receiving power from the stock rail as that can cause the dreaded DCC momentary short circuit when you change the point. The relay I'm using is this one -

http://www.jprelec.co.uk/store.asp/c=751/Hongfa-HFD2-Latching-DPCO-Relays

[Kenton]

1 - always (and do not forget to isolate the frog rails to the following track (and in DCC make sure the following tracks both get power from elsewhere - or no sound/lights/action)

2 - not for modern N stock but very likely with old N ... and particularly steam locos with pony trucks as they bounce all over the place. Don't forget all those other stock items with metal wheels.

[David Rickard]

Well I've got no problem modding them as per option 2. It'd be fiddly, but entirely doable. It'd also insure against the issue with the blades not changing as fast as the relays on the point indicators. It sounds entirely reasonable.

[bigdaveadams1]

Has anyone experienced using method 1 with Cobalt motors? I just wonder how quickly the polarity switch operates in relation to the slow action on the point motor.